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An extension of Tutte's formula 60 years later

An extension of Tutte's formula 60 years later

Given a set of deformable polygons with prescribed numbers of sides, in how many inequivalent ways can one glue them edge to edge so as to build a sphere? This mathematical question, which pertains to map combinatorics in random geometry, was partially answered by the mathematician William Tutte in a famous 1962 article "A census of slicings" where he solves the problem in the particular case where all the polygons, except at most two of them, have an even number of sides. In a recent article, Jérémie Bouttier and Emmanuel Guitter (IPhT), in collaboration with the mathematician Grégory Miermont (ENS de Lyon), succeeded, 60 years later, in extending Tutte's formula to the most general case, namely for polygons whose numbers of sides have arbitrary parities. Even though more complex, their general explicit formula is still very elegant and conceals numerous symmetries. It is with no doubt the starting point for new combinatorial discoveries.

A Starting ERC Grant for Ben Wieder

A Starting ERC Grant for Ben Wieder

Ben Wieder, researcher at the Institut de Physique Théorique, has just been awarded an ERC Starting grant in the field of topological insulators

Death of Michel Gaudin (02/12/1931 -- 04/08/2023)

Death of Michel Gaudin (02/12/1931 -- 04/08/2023)

Michel Gaudin, French mathematical physicist, engineer from the Ecole Polytéchnique (Class 1951) and Ingénieur des Ponts et Chaussées, died on August 4th, 2023, aged ninety-two years old. Gaudin joined the Commissariat à l'Énergie Atomique in 1956, first in the Service de Neutronique Expérimentale, then in the Service de Physique Théorique (later Institut de Physique Théorique, IPhT). He spent his entire career there, with the exception of one year at Stony Brook in 1970.

Henry Navelet (1938-2023)

Henry Navelet (1938-2023)

Henri Navelet died on July 3, 2023 in Bordeaux, at the age of eighty-four.

Efficient algorithms for scattering amplitudes

Efficient algorithms for scattering amplitudes

By establishing an original connection between Feynman integrals and algebraic geometry, a team led by the IPhT has tackled the challenge of computing "scattering amplitudes," which form the basis for the interpretation of particle physics experiments, among other things.

Matt Von Hippel is to join IPhT on September 1.

Matt Von Hippel is to join IPhT on September 1.

Matt von Hippel went to Stony Brook University for his doctoral studies after obtaining an undergraduate degree at Tufts. He obtained his PhD in 2014, on N=4 supersymmetric Yang-Mills theory. His advisor was Michael Douglas. During his PhD he developed a method to bootstrap perturbative scattering amplitudes in quantum field theories. He then spent three years as a postdoc at the Perimeter Institute, where he continued working on bootstrapping higher-loop amplitudes in the N=4 theory. In 2017, he moved to the Niels Bohr Institute in Copenhagen, first as a postdoc and later as an Assistant Professor. Matt is interested in the broad variety of integral functions that appear in scattering amplitudes. He seeks to understand them using novel integration methods. He has already discovered surprising iterative structures in them.

Antoine Bourget joins the IPhT as a permanent researcher!

Antoine Bourget joins the IPhT as a permanent researcher!

We are pleased to announce that Antoine Bourget will join the IPhT permanent researchers team, as of September 1, 2023. After studies at Ecole Polytechnique and Ecole des Mines, Antoine Bourget did a Ph.D. at LPTENS, followed by post-doctoral studies at the University of Oviedo, Imperial College London, and IPhT (joint with LPENS). Antoine is an expert of strong coupling phenomena in quantum field theory, which encapsulate the vast field of problems outside the reach of perturbation theory, from classical field configurations (monopoles, instantons) to quantum effects (quark confinement, low-energy structure of the proton). Using algebra and geometry, he has been striding the bridge provided by string theory and supersymmetric field theory to address the far-reaching problem of the classification of conformal field theories and the study of the renormalization group flows connecting them. Welcome among us Antoine!

The Benchmark for Quantum Computer Performance (BACQ)

The Benchmark for Quantum Computer Performance (BACQ)

The BACQ project, launched as part of France's national quantum strategy within the LNE's MetriQs program, aims to establish a benchmark for evaluating the performance of future quantum computer technologies. Coordinated by Thales, the consortium involves three CEA institutes. The consortium is crucial for the development of quantum computing, and will also be crucial for industrial end-users. Quantum computing is set to revolutionize a wide range of technical fields and business sectors, from optimization in logistics, finance and scheduling, to simulation in research, engineering and industry. But how to measure the performance of the various technologies being developed for future quantum computers, with objectivity, reliability and comparability? And this, in a context of media hype and strong competition. This is the challenge of the BACQ project, which aims to establish quantitative, meaningful and ergonomic benchmarks for end users in the industry.

Nomination of Henri Orland to the American Academy of Arts and Sciences

Nomination of Henri Orland to the American Academy of Arts and Sciences

The election to the American Academy of Arts and Sciences of our friend and colleague Henri Orland (Institute of Theoretical Physics) crowns an outstanding scientific career dedicated to fundamental research. Henri Orland's work in statistical physics has led to essential advances in our understanding of disordered systems, combinatorial optimization, and the study of soft matter, while also giving rise to original applications to the biophysics of nucleic acid and protein folding and to the problem of sequence alignment in molecular biology. Full text: FM_Orland_EN.pdf (2.8 Mo)

Calculating the Witten-Kontsevich intersection numbers

Calculating the Witten-Kontsevich intersection numbers

The "Witten-Kontsevich intersection numbers" are scattering amplitudes in the context of the most simplified possible model of quantum gravity and string theory: a very low-energy quantum gravity, simplified to the extreme to keep only the fundamental phenomenon of topology fluctuations. These are positive integer or rational numbers, and they are the basis of all the more complex string theories, and of all surface enumerative geometry, in particular in algebraic geometry. Moreover, the conjecture of E. Witten, whose proof gave the Fields Medal to M. Kontsevich, indicates that these same numbers are relevant in almost all problems of mathematical physics: random matrices, statistical physics on a random surface, wave propagation in a canal, or the semi-classical approximation of the solutions of Schrödinger equations, and of all field theories in quantum physics. In particular, they play an important role in the black-hole model developed by Jackiw-Teitelboim.

Monica Guica receives the CNRS bronze medal for the year 2023!

Monica Guica receives the CNRS bronze medal for the year 2023!

Since 2016 Monica Guica has been working at the Institute of Theoretical Physics in Saclay (CEA/CNRS) in the field of the relation between quantum gravity and conformal quantum theories. In particular, she explores the correspondence between quantum gravity on a spacetime and certain field theories based on the edge of the first spacetime. Using a term used in optics, this correspondence is called "holographic" because all the information contained in a black hole is coded on its surface. This medal rewards her work, in particular that on the integrable deformation of type "J TBar" (J being a current and TBar a component of the tensor-energy impulse) of a two-dimensional field theory invariant by conformal transformations [2]. Congratulations Monica! Links: CNRS' announcement https://arxiv.org/abs/1710.08415 CEA/DRF's announcement

27th Itzykson Conference : Fluctuations far from Equilibrium

27th Itzykson Conference : Fluctuations far from Equilibrium

We are glad to inform you that the 27th ITZYKSON CONFERENCE will be held from Wednesday, the 31st of May in the morning, to Friday the 2nd of June at the Institut de Physique Theorique (IPhT), CEA Universite de Paris-Saclay. This year the ITZYKSON CONFERENCE will be devoted to "Fluctuations far from Equilibrium". You can find more details on the web-page dedicated to this event: https://indico.in2p3.fr/event/29430/ We hope that the conference will attract the interest of many participants. We would be grateful if you could register at : https://indico.in2p3.fr/event/29430/registrations/3507/ This will take you a very little time but it will be of great help to us for practical matters. Best regards, Tomohiro Sasamoto, Laure Sauboy and Kirone Mallick.

2023 Galileo Galilei Medal for David Kosower (IPhT), Zvi Bern(California U) and Lance Dixon (SLAC)

2023 Galileo Galilei Medal for David Kosower (IPhT), Zvi Bern(California U) and Lance Dixon (SLAC)

The 15th of February, birthday of Galileo Galilei, the 2023 Galileo Galilei Medal of INFN and GGI has been awarded "for the development of powerful methods for high-order perturbative calculations in quantum field theory" to David Kosower, researcher at the Institut de Physique Théorique, Zvi Bern(California U) and Lance Dixon (SLAC). Congratulations! INFN Press release

Quantum networks : Entangled ions across the university campus Innsbruck

Quantum networks : Entangled ions across the university campus Innsbruck

Trapped ions are one of the leading systems to build quantum computers. To link multiple such quantum systems, interfaces are needed through which the quantum information can be transmitted. Until now, trapped ions were only entangled with each other over a few meters in the same laboratory. Researchers from the university of Innsbruck succeeded to entangle two trapped ions located in two labs separated by 230 meters. These efforts have been supported by a theoretical model of a single trapped ion including most of experimental noise sources. The model, developed at IPhT, provided a guidance for the experimentalists, showing for example what to expect when increasing the distance or helping to identify the most detrimental noise sources. With the entanglement of far away ions, Austrian researchers show that trapped ions are a promising platform for future quantum networks that span cities and eventually continents.

Hamiltonian paths, a challenge for KPZ.

Hamiltonian paths, a challenge for KPZ.

Examples of measured exponents and their comparison to KPZ predictions, before and after renormalization The famous KPZ formulas (Knizhnik-Polyakov-Zamolodchikov, 1988) relate the critical exponents of statistical models on regular two-dimensional lattices to the exponents of the same models on planar random lattices. These relations, verified exactly in a large number of statistical mechanics systems, have now acquired a rigorous mathematical status, under certain technical assumptions of statistical independence. Hamiltonian paths on lattices, which are self-avoiding paths forced to visit all the sites of the lattice, constitute a critical statistical model where the geometrical constraints are particularly strong.

Kibble-Zurek phenomenon: from the early Universe to a spin chain

Kibble-Zurek phenomenon: from the early Universe to a spin chain

Figure caption: The form factor (dimensionless product of density of domain walls and magnetic susceptibility) provides a novel measure of the distance to thermal equilibrium. Red dot: unit equilibrium value. Green dot: value in zero-temperature coarsening regime. Blue interval: possible range of form factor for everlasting and other kinds of very slow quenches. What happens when a system is cooled very slowly from its high-temperature phase through a critical point corresponding to a continuous (i.e., second-order) thermal phase transition? This question was addressed in 1976 by Sir Thomas Kibble in the context of the cosmology of the primordial Universe. His goal was to predict the density of relic topological defects (non-trivial field configurations such as monopoles or cosmic strings) that are left behind after the expanding and cooling Universe has undergone one or more continuous phase transitions.

Kirone Mallick winner of the 2022 Physics French Society (SFP) Paul Langevin Prize

Kirone Mallick winner of the 2022 Physics French Society (SFP) Paul Langevin Prize

The jury of the Langevin Prize, meeting on 10 January 2023, awarded Kirone Mallick, physicist at the IPhT, the 2022 Langevin Prize of the French Physical Society for his remarkable work in statistical physics and concerning stochastic processes. Kirone Mallick works at the Institut de Physique Théorique in Saclay (CEA/CNRS) in the field of non-equilibrium statistical physics. As a specialist in exact solutions, he develops analytical approaches in which one-dimensional exclusion models play an important role. His work combines physical intuition and mathematical dexterity in a remarkable way. The breakthroughs he has made on paradigmatic models of statistical physics use an arsenal of methods ranging from classical and quantum integrability to more macroscopic approaches focusing on fluctuations or large deviations. His work on single-file diffusion brilliantly illustrates the complementarity between these different methods.

A natural mechanism for

A natural mechanism for "uplifting" the cosmological constant in string theory

Caption: The string theory solution is a product of a four-dimensional universe times a small six-dimensional space. The cosmological constant (Λ) is the minimum value of the potential energy, here plotted as a function of the volume of the six-dimensional manifold. The cosmological constant before the “uplifting” (red curve) is negative, while after it (blue curve) is positive and tiny, as that of our universe. Experiments reveal that our universe has an accelerating expansion, which, in the context of general relativity, requires the positivity of Einstein's cosmological constant. A positive cosmological constant poses several problems in the context of quantum gravitational theories. String theory, one of the most developed theories of quantum gravity, has been struggling to find solutions of the equations of motion that include a four-dimensional space with positive cosmological constant.

EPS PhD prize awarded to IPhT student

EPS PhD prize awarded to IPhT student

The Nuclear Physics Division of the European Physical Society has awarded Giuliano Giacalone, a former student of IPhT, its PhD prize. This prize is awarded every third year, and the ceremony took place during the EuNPC 2022 conference in Santiago de Compostela, Spain, in October 2022. https://indico.cern.ch/event/1104299/page/26561-npd-2021-phd-prize-winners Giuliano, now a postdoc at the University of Heidelberg, completed his PhD thesis "Observing the shape of nuclei at high-energy colliders" in November 2020 under the supervision of Jean-Yves Ollitrault. His thesis has previously been honoured with an award of the French Physical Society. https://www.sfpnet.fr/accessits-prix-jeunes-chercheurs-euses-2020-de-la-sfp Congratulations!

Exact results for the

Exact results for the "box ball system", a cellular automaton with solitons

Figure caption: The rules governing the dynamics of the balls in the "box ball system" can be illustrated with the help of a carrier that loads and unloads the balls by running through the system from left to right at each time step. Understanding how macroscopic laws and large-scale properties emerge from the microscopic interactions between the constituents of a system is a major problem in statistical physics. One can for instance consider the appearance of hydrodynamic behaviors or the way currents react to external forces. It is generally very challenging to connect the microscopic rules to these large-scale properties, and there are relatively few systems for which exact results can be obtained. The “Box-ball system” (BBS), a particular cellular automaton, is such an example. The BBS consists of “balls” occupying “boxes” arranged on a line, with at most one ball per box.

Exact Macroscopic Fluctuations Far from Equilibrium

Exact Macroscopic Fluctuations Far from Equilibrium

Many natural systems remain far from thermodynamic equilibrium by exchanging matter, energy or information with their surroundings. As these transfers, or fluxes, break timereversal invariance, such processes are beyond the realm of traditional thermodynamics and their statistical fluctuations do not follow the principles of equilibrium statistical mechanics. Though a fully general theory of non-equilibrium systems still remains to be constructed, a physical principle describing the macroscopic behaviour of diffusive systems far from equilibrium has been proposed by G. Jona-Lasinio and his collaborators in 2001: this is the Macroscopic Fluctuation Theory (MFT). In the MFT framework, macroscopic fluctuations far from equilibrium are determined by two coupled non-linear hydrodynamic equations. However, for a long time, the MFT equations have remained intractable. In a recent work that has appeared in Physical Review Letters, K. Mallick (IPhT), H. Moriya and T.

Preparation of the exploitation of the Euclid mission

Preparation of the exploitation of the Euclid mission

The IPhT is strongly involved in the preparation of the scientific exploitation of the Euclid mission. This participation is done at two levels. Francis Bernardeau is in charge of the coordination of the Science Performance Verification, an exercise that aims to ensure that the core objectives of the mission - constraints on the parameters of the dark energy equation of state - will be achieved given what is known about the general parameters of the mission. But more generally, the IPhT researchers are involved in the preparation of the tools necessary for the analysis of cosmological data. In particular, it is a question of developing and validating the tools allowing to predict the expected observables for a large variety of cosmological models. Thus, Filippo Vernizzi coordinates the efforts within the Euclid consortium to develop simulations and theoretical tools to study the non-linear development of modified gravity models.

Maps day at IPhT on 24 June 2022

Maps day at IPhT on 24 June 2022

In the past 10 years, the French community working on maps on surfaces has come together several times per year during the so-called "maps days". The next edition of these maps days will take place at IPhT on Friday 24 June 2022. The scientific program is as follows: see also the webpage Program: 10h15-11h15 : Nicolas Curien (Université Paris-Saclay), Parking on the infinite binary tree 11h30-12h30 : Fedor Levkovich-Maslyuk (Université Paris-Saclay / CEA), Critical phenomena for dually weighted graphs and spanning forests via matrix models 14h-15h : Zéphyr Salvy (Université Gustave Eiffel), Random planar maps decomposed into blocks: a phase study 15h15-16h15 : David Keating (University of Wisconsin-Madison), k-tilings of the Aztec diamond The talks will take place in person in the Bloch amphitheater.

Quantum bounds and fluctuation-dissipation relations

Quantum bounds and fluctuation-dissipation relations

The chaotic behaviour of classical non-linear systems is an ubiquitous effect which refers to the unpredictability of their complex dynamics, a phenomenon known as the butterfly effect. In mathematical terms this concept is characterized by the so-called Lyapunov exponent, a quantity which expresses the rate at which trajectories which start from close-by initial conditions (position and velocity), diverge with time. In quantum mechanics it is difficult to find good diagnostics of chaos and this question has been intensively debated since the beginnings of quantum mechanics. Recently, groundbreaking results from high energy physics [1] showed that quantum mechanics imposes a strict bound on the Lyapunov exponent. This novel effect has motivated enormous interest over different fields, leaving, however, several outstanding open questions.

26th Itzykson conference: Black-Hole Microstructure IV

Conference: June 6-10 - Workshop: June 13-17

26ème conférence Itzykson : "Black-Hole Microstructure IV"

La description microscopique des trous noirs est un défi depuis plus de quarante ans. Il existe aujourd'hui un certain nombre d'approches prometteuses pour résoudre ce problème et l'objectif principal de cette conférence et de ce workshop est de réunir des experts dans ces domaines afin d'identifier les synergies, de s'engager dans une critique constructive et de résoudre les conflits apparents. Une attention particulière sera accordée à la dynamique de la microstructure des trous noirs : comment la matière entrante est brouillée et comment l'information est récupérée. La conférence se tiendra seulement en ligne le lundi 6 juin (jour férié en France) puis en personne à l'IPhT, CEA-Saclay du mardi 7 au vendredi 10 juin. Chaque jour de la conférence sera également retransmis. Inscription sur le site web.

Colloquium Rencontres de l'IPhT in Autrans (Vercors) from 23 to 25 May.

Colloquium Rencontres de l'IPhT in Autrans (Vercors) from 23 to 25 May.

The next colloquium Rencontres de l'IPhT conference will be held in Autrans (Vercors) from 23 to 25 May. It will consist of conferences and lectures concerning both the major fields of research in theoretical physics and supporting activities. The main themes of physics will be: - Mathematical physics: group A - Cosmology, particles and nuclei: group B - Statistical physics - condensed matter: group C Main goals: - To share knowledge on scientific topics and strengthening cohesion within the Institute. - To bring together all of the Institute's collaborators in order to discuss common subjects and activities and to strengthen interactions between members of the different teams, including support. - To unite the teams around a common project. See you soon in Autrans!

An extension of Tutte's formula 60 years later

An extension of Tutte's formula 60 years later

Given a set of deformable polygons with prescribed numbers of sides, in how many inequivalent ways can one glue them edge to edge so as to build a sphere? This mathematical question, which pertains to map combinatorics in random geometry, was partially answered by the mathematician William Tutte in a famous 1962 article "A census of slicings" where he solves the problem in the particular case where all the polygons, except at most two of them, have an even number of sides. In a recent article, Jérémie Bouttier and Emmanuel Guitter (IPhT), in collaboration with the mathematician Grégory Miermont (ENS de Lyon), succeeded, 60 years later, in extending Tutte's formula to the most general case, namely for polygons whose numbers of sides have arbitrary parities. Even though more complex, their general explicit formula is still very elegant and conceals numerous symmetries. It is with no doubt the starting point for new combinatorial discoveries.

$SLE multifractal news$

SLE multifractal news

Bertrand Duplantier (IPhT) and his collaborators have just obtained an exact expression for the generalized multifractal spectrum, which characterizes the highly singular behavior of the universal fractal curve, here arcuate in a semi-infinite logarithmic spiral, and associated with Schramm-Loewner Evolution (SLE), a paradigmatic planar stochastic process. The method of passage through Liouville quantum gravity is successfully applied there. The attached file contains a simplified presentation of this mathematical physics result. Developped results

Dark energy in the Laboratory?

Dark energy in the Laboratory?

Very light scalar fields could be at the origin of large-scale phenomena such as dark energy. Unfortunately, they would also lead to large deviations in solar system physics. For instance, they would appear as fifth forces and deviate planets in their orbits around the Sun. This can be avoided if their local effects are screened. Screening mechanisms are now well understood and currently tested in the laboratory. Associated light scalar particles could also be created from photons in dense environments in the presence of intense magnetic fields. This could happen deep inside the Sun where magnetic fields can reach several Tesla. These light particles would then propagate through the interplanetary medium and penetrate the earth’s atmosphere. Detectors such as XENON1T, originally designed to detect the presence of dark matter, can be used to track the passage of these elusive light particles. In 2020, the XENON1T experiment claimed to have seen an unexpected signal.

Planck 2022

Mariana Graña and Stéphane Lavignac, researchers at the IPhT, are among the organizers of the 2022 session of the Planck Conference Series « From the Planck scale to the electroweak scale ». The conference will be held in Paris from May 30 to June 2nd, complemented on June 3rd by a special day dedicated to Ignatios Antoniadis, one of the founders of these conferences.

Public talk of Stephane Lavignac on Tuesday March 15th

Public talk of Stephane Lavignac on Tuesday March 15th

Stéphane Lavignac (IPhT) will be giving a public talk (in French) about « Les neutrinos Les neutrinos, ces particules mystérieuses qui interrogent les physiciens on Tuesday, March 15th at 7 pm in the framework of the Conférences Université Citoyenne at the Patronage laïque Jules Vallès in Paris. https://www.patronagelaique.eu/event-details/les-neutrinos-ces-particules-mysterieuses-qui-interrogent-les-physiciens-1 You also can find this conference on Youtube: Conferences

A new book written by Marc Barthélémy about spatial networks

A new book written by Marc Barthélémy about spatial networks

This book Spatial Networks - a complete introduction : From Graph Theory and Statistical Physics to Real-World Applications provides a complete introduction into spatial networks. It offers the mathematical tools needed to characterize these structures and how they evolve in time and presents the most important models of spatial networks. All the theoretical discussions are illustrated on real-world examples.

A new solution for the observation of Higgs Boson and Neutron Electric Dipole

A new solution for the observation of Higgs Boson and Neutron Electric Dipole

The value of the Higgs boson mass and of the neutron electric dipole moment (EDM) have been mysterious for decades. They remain among the deepest open questions in particle physics. Until now they have been treated separately, as they are related to very different symmetries and physical processes. Raffaele Tito D'Agnolo (IPhT Saclay) and Daniele Teresi (CERN) recently proposed a joint solution to the two problems, based on the observation that a single operator in our current theory of Nature has a special sensitivity to both parameters. In their model a Multiverse is populated at early times, as shown in the Figure. It is composed of universes with different values of the fundamental parameters of Nature. A fraction of a second after the birth of these universes, the vast majority of them "crunches" becoming much smaller than an atom.

Cédric Villani at IPhT on March 1st

Cédric Villani at IPhT on March 1st

We will have the pleasure to welcome Cédric Villani at IPhT on Tuesday, March 1st morning. Mathematician, Cédric Villani is a university professor, laureate of the 2010 Fields medal and former director of Institut Henri Poincaré. He is also deputy (MP) for Essonne's 5th constituency in the National Assembly of France. Here is the program of the meeting : 09:00-09:10 introduction, by Catherine Pépin et François David 09:10-10:00 scientific talk by Cédric Villani 10:00-10:30 break 10:30-11:30 talks by IPhT members : Kirone Mallick, Philippe Brax, Jérémie Bouttier 11:30-12:00 question session, chaired by Bertrand Duplantier Conference site The meeting will take place in amphi Bloch and will be streamed online via BBB and on www.youtube.com/c/IPhTTV.

Summer School in Cargèse around exotic superconductivity

Summer School in Cargèse around exotic superconductivity

We announce the ExoSup Summer School on unconventional superconductivity,co-organized by Catherine Pépin from IPhT..It will take place at the Institut d'Etudes Scientifiques de Cargèse from June 13 to 25, 2022.

Langevin Prize of the French Society of Physics for Mariana Graña

Langevin Prize of the French Society of Physics for Mariana Graña

Good news for the IPhT, Mariana Grana has just received the Langevin Prize of the French Society of Physics! Congratulations to Mariana for this well deserved success! Prize citation:

Arrival of Luc Blanchet

Arrival of Luc Blanchet

We warmly welcome Luc Blanchet, who will be a regular visitor of the IPhT during the next six month.

Junior Permanent Position in Theoretical Quantum Physics at IPhT

Junior Permanent Position in Theoretical Quantum Physics at IPhT

The Institut de Physique Théorique invites applications for a junior CEA permanent position in quantum condensed matter theory or/and quantum information sciences. Candidates with interest in one of the following scientific areas will be considered with the highest priority: Quantum matter, quantum and topological materials, classical and quantum simulations, quantum computing, quantum communication Interested candidates should apply via AcademicJobsOnline (Job #20967) and applications should be received by March 1st, 2022 in order to receive full consideration. Contact: position2022@ipht.fr

Junior Permanent Position in Theoretical Physics at IPhT

Junior Permanent Position in Theoretical Physics at IPhT

The Institut de Physique Théorique invites applications for a junior CEA permanent position in theoretical physics. Candidates with interest in one of the two following scientific areas will be considered with the highest priority: « High-energy phenomena and quantum field theory, from amplitudes and integrability to gravitational waves » « Applications of statistical physics: physics of life, artificial intelligence, neuroscience, complex systems, etc.». Interested candidates should apply via AcademicJobsOnline (Job #20703) and applications should be received by Feb. 15, 2022 in order to receive full consideration. Contact: position2022@ipht.fr

Un lien entre la masse du boson de Higgs et la constante cosmologique

Un lien entre la masse du boson de Higgs et la constante cosmologique

Pendant des décennies nous avons progressé dans l'étude des lois fondamentales de la nature à travers les collisionneurs des particules. Le Grand Collisionneur de Hadrons (LHC) a eu un impact énorme sur notre connaissance de la physique des particules. Une des conséquences les plus importantes de ce programme expérimental est que la valeur de la masse du boson de Higgs et son origine restent mystérieux.

Conférence exceptionnelle de Cédric Villani le lundi 22 novembre à 19h30 (Institut Pascal)

Conférence exceptionnelle de Cédric Villani le lundi 22 novembre à 19h30 (Institut Pascal)

l’Institut Pascal à l’Université Paris-Saclay organise pendant six semaines avec le concours de plusieurs physiciens dont Philippe Brax de l’IPhT (du 18 octobre au 26 novembre 2021) des exposés pour le grand public, donnés par des physiciens de renom. Dans ce cadre, Cédric Villani donnera une conférence exceptionnelle le lundi 22 novembre à 19h30 (Institut Pascal) sur le thème La flèche du temps, du billard moléculaire à la danse des astres. l’accueil du public se fait à partir de 19h. Vous pourrez avoir davantage d’informations via ces liens : https://indico.ijclab.in2p3.fr/event/7119/ Renseignements pratiques et localisation de la conférence Affiche en PDF

Série de conférences sur l’utilité des simulateurs et des ordinateurs quantiques pour résoudre des grands problèmes en physique.

Série de conférences sur l’utilité des simulateurs et des ordinateurs quantiques pour résoudre des grands problèmes en physique.

Nous organisons à l’IPhT une série de conférences sur l’utilité des simulateurs et des ordinateurs quantiques pour résoudre des grands problèmes en physique. voir https://qcs.quantum.paris pour davantage d'informations.

Giorgio Parisi Nobel Prize in Physics 2021

Giorgio Parisi Nobel Prize in Physics 2021

The Nobel Prize in Physics 2021 has been awarded to Giorgio Parisi for his work in statistical physics, with the other half going to two specialists in climate modeling. Giorgio Parisi, professor at the University of Rome "La Sapienza", has made numerous stays in the Paris region, where he has established many collaborations. Giorgio Parisi has been distinguished for his work on disordered systems: The Sherrington-Kirkpatrick model in the first place (a mean-field spin glass model), for which he found the solution "with a very unconventional method" and revealed a surprisingly complex and totally new physics. The Edwards-Anderson model then (a spin glass model on a lattice), with both analytical and numerical methods.

Problems in Quantum Field Theory : a book by François Gelis.

Problems in Quantum Field Theory : a book by François Gelis.

Francois Gelis's book, Problems in Quantum Field Theory, largely inspired by his QFT lectures in the Master program High Energy Physics at Ecole Polytechnique, has just been published by Cambridge University Press. This new book is a follow-up on his earlier textbook, "Quantum Field Theory", published by CUP in 2019. Editor's page

Mathematical Harmony and the Quantum World

Mathematical Harmony and the Quantum World

A conference honouring the 60 years anniversary of our former colleague Denis Bernard will take place at the ENS Paris : 45 rue d’Ulm, Salle Dussane - October 14-16, 2021.

Avec une mémoire quantique, l’ordinateur quantique « maigrit » d’un facteur mille !

Avec une mémoire quantique, l’ordinateur quantique « maigrit » d’un facteur mille !

Des physiciens théoriciens de l'IPhT montrent qu'en dotant un processeur quantique d'une mémoire quantique, il est possible de réduire de trois ordres de grandeur le nombre de bits quantiques nécessaires à la résolution d'un problème emblématique.

The art of mathematical physics

The art of mathematical physics

Our friend and colleague Hubert Saleur has recently turned 60. A conference celebrating his anniversary and focusing on his numerous contributions to condensed matter physics, low-dimensional quantum field theory, and mathematical physics will take place at the IPhT on September 20-23, 2021. Participation and talks will be in hybrid mode. On-site participants will have to wear masks inside the Institute building and will have to show a valid immunisation certificate or a valid negative test for SARS-CoV-2 (of less than 72 hours) upon registration on Monday morning. Since the maximum capacity of the Amphi Claude Bloch is restricted to 50 persons, registration is necessary. More details can be found on the webpage of the conference : http://www.phys.ens.fr/~jacobsen/AMP21.html Organisers: Jesper Jacobsen (ENS Paris), Didina Serban (IPhT Saclay), Nicholas Warner (USC Los Angeles)

Correlation functions and wave functions in solvable models

Correlation functions and wave functions in solvable models

The meeting will be held at the Institut de Physique Théorique (IPhT-CEA) in Saclay from Sept 13 to 15 and at the Ecole Normale Supérieure (ENS) in Paris on Sept 16. It will bring together experts in the field of integrable systems and address important open questions in the calculation of correlation functions and wave functions in integrable models, with applications to N=4 Super-Yang-Mills theory, Heisenberg spin chains and 2d relativistic QFTs. Participation will be in person only. Participants will have to wear masks inside the Institute building and will have to show a valid immunisation certificate or a valid negative test for SARS-CoV-2 (of less than 72 hours) upon registration on Monday morning. The maximum capacity of the Amphi Claude Bloch being restricted to 50 persons, registration is necessary and it can be done via the corresponding link on the webpage of the conference: https://indico.in2p3.

Deux étudiants de l'IPhT primés!

Deux étudiants de l'IPhT primés!

Accessit au prix Saint-Gobain pour Giuliano Giacalone La Société française de physique (SFP) a décerné l'accessit du prix Saint-Gobain 2020 à Giuliano Giacalone pour sa thèse. Giuliano a passé 5 mois à l'IPhT pour son stage de M1 en 2016, puis il est revenu en octobre 2017 pour y préparer sa thèse sous la direction de Jean-Yves Ollitrault, qu'il a soutenue le 30 novembre 2020. Dans cette thèse, il prouve que les collisions ultra-relativistes entre des noyaux déformés permettent de mesurer leur déformation de manière plus directe que les expériences traditionnelles de physique nucléaire de basse énergie.

Black-hole microstructure conference (June 7th - 11th, 2021)

Black-hole microstructure conference (June 7th - 11th, 2021)

The microscopic description of black holes has been a challenge for more that forty years. There are now quite a number of promising approaches to solving this problem and the primary goal of this conference and workshop is to bring together experts in these areas to identify synergies, engage in constructive criticism and resolve apparent conflicts. A significant focus will be the dynamics of black-hole microstructure: how infalling matter is scrambled and how information is recovered. The conference will involve three or four talks a day and three panel discussions. All events will be held via Zoom and streamed to Youtube Organizers: Iosif Bena and Nick Warner

25th C. Itzykson Conference (June 2-4, 2021):

25th C. Itzykson Conference (June 2-4, 2021): "Many-Body Chaos, Scrambling and Thermalization in Interacting Quantum Systems"

Thermalization and out of equilibrium dynamics of many body strongly interacting quantum systems have been the subject of a recent burst of research activities. In particular the dynamics of operator and information spreading (scrambling) as well as its chaotic behavior have been recently investigated starting from models originated in the context of strongly correlated many body systems and have found application to black holes physics. This has been triggered by the appearance of a new class of exactly soluble large N quantum field theories, such as the celebrated Sachdev-Ye-Kitaev model. The aim of this workshop is to review the recent advances in the field and to stimulate further research in this direction which lies at the interface between statistical and condensed matter physics and high-energy/mathematical physics. Due to the current situation, the conference will take place online.

Multipole Ratios : A New Window into Black Holes

Multipole Ratios : A New Window into Black Holes

CC BY 3.0 (as fig. 1 from Event Horizon TelescopeCollaboration, K. Akiyama et al., First M87 Event Horizon Telescope Results. V. Physical Origin of the Asymmetric Ring, Astrophys.J. Lett.875(2019), no. 1, L5,1906.11242 ) More than a century after their theoretical discovery, black holes still hold many mysteries. We have developed new methods to calculate an infinite number of hitherto unknown parameters of any arbitrary black hole, some of which we believe could be observed in current and future experiments. Half of these multipoles are finite, and the other half vanish. Any ratio of two vanishing moments thus seems to be ill-defined. By embedding black holes in string theory, we develop a novel method to define and calculate such multipole moment ratios unambiguously for any black hole. In this way, we find an infinite number of previously unknown multipole ratios for any Kerr black hole.

Orazio Scarlatella lauréat du prix de thèse Physique des Ondes et de la Matière (PhOM) 2020

Orazio Scarlatella lauréat du prix de thèse Physique des Ondes et de la Matière (PhOM) 2020

Orazio Scarlatella, former doctoral student at IPhT, is the winner of the 2020 PhD prize "Physics of Waves and Matter" of the Physics Graduate School of the University of Paris-Saclay, in the speciality "Theoretical Physics, Numerics and Modelling". Orazio Scarlatella's thesis work focuses on the dynamics of dissipative quantum many-body systems. These problems are of great richness and complexity because they combine the effects of interactions, quantum fluctuations, and out-of-equilibrium physics. The work of O. Sacarlatella consisted of several new conceptual and methodological developments in this field at the interface between correlated materials and quantum optics, with applications to systems such as arrays of superconducting cavities or ultra cold atoms trapped in optical arrays.

Modeling the city: an equation ends centuries-old controversies

Modeling the city: an equation ends centuries-old controversies

(c) Leo Patrizi Marc Barthelemy and Vincent Verbavatz proposed a new equation to understand the distribution of urban populations in a country and their results are published in the journal Nature (online November 18, 2020) This equation, constructed from data for several countries, accounts for the first time for the temporal variations of urban populations and their organization. This stochastic equation of a new type (with two multiplicative noises, one gaussian and the other of the Levy type) highlights the importance of “interurban migratory shocks”, rare but significant population movements, and makes it possible to understand the hierarchical structure of cities and statistical regularities such as Zipf's law. More information and the interview with Marc Barthélémy

Quantum entanglement: A single photon takes two optical paths by

Quantum entanglement: A single photon takes two optical paths by "entangling" them!

An IPhT researcher, Nicolas Sangouard, and his partners from the universities of Geneva and Basel have succeeded for the first time in "intriguing" the outputs of two optical fibers sharing a single photon at a distance of 2 km. By this performance, they show how a form of quantum entanglement that is simple to produce can be distributed and detected over long distances. An important step towards the construction of a secure quantum the internet! Quantum entanglement or entanglement refers to a very surprising phenomenon in which two systems form a linked state, with the state of each individual system remaining undefined. Regardless of the distance between them, these systems have correlated physical properties. Without stopping being amazed, physicists have learned to use entanglement and to imagine technological applications that have no classical equivalent.

An strongly secured encryption

An strongly secured encryption

How do we protect the privacy of a communication if we cannot trust the devices used to communicate? Researchers from IPhT, the University of Basel and ETH Zurich have provided innovative answers to this question, which is at the heart of research in quantum cryptography. Hackers in possession of quantum computers pose a serious threat to some of today's crypto-systems. An interesting solution uses encryption methods based on keys produced by quantum principles. However, current quantum encryption protocols assume that the devices used to communicate are known and trustworthy. Otherwise, a door is opened for eavesdropping. A team of physicists around Nicolas Sangouard from IPhT and the University of Basel, as well as Professor Renato Renner from ETH Zurich, have developed the theoretical bases of a communication protocol that offers ultimate protection of the privacy and can be implemented experimentally.

David Kosower lauréat de l'ERC Advanced Grant

David Kosower lauréat de l'ERC Advanced Grant "Ampl2Einstein"

David Kosower vient d’obtenir l’ERC Advanced Grant Ampl2Einstein. Ce projet sera consacré au développement de nouveaux calculs perturbatifs pour l’étude de l´émission d´ondes gravitationnelles lors de la fusion de trous noirs ou d'étoiles à neutrons. Ces calculs de précision sont une étape cruciale afin de pouvoir extraire des observations des informations sur la structure de ces astres. L' ambition du projet “Ampl2Einstein” est de repousser les limites de la théorie quantique des champs et de développer le lien entre théories de Yang-Mills et théories de gravitation.

Network Physics and covid19

Network Physics and covid19

A virus spreads over the "contact network" whose nodes are individuals, and the link represents the possibility for the virus to spread between them. This contact network is therefore not necessarily equivalent to our social network and has a very complex structure. The study of this type of network is used today in epidemiology to understand how a virus spreads. Liberation released today an interview with Marc Barthelemy, director of research at the Institute of theoretical physics (CEA).

Un nouvel ouvrage co-écrit par Pierfrancesco Urbani, physicien à l’IPhT

Un nouvel ouvrage co-écrit par Pierfrancesco Urbani, physicien à l’IPhT

Le nouvel ouvrage Theory of simple glasses, co-écrit par Giorgio Parisi, Pierfrancesco Urbani , physicien à l’IPhT, et Francesco Zamponi, vient de paraître chez Cambridge University Press. Félicitations Pierfrancesco !

Un nouvel ouvrage co-écrit par Henri Orland, physicien à l'IPhT

Un nouvel ouvrage co-écrit par Henri Orland, physicien à l'IPhT

Le nouvel ouvrage Molecular Kinetics in Condensed Phases: Theory, Simulation, and Analysis, écrit par Ron Elber, Dmitrii E. Makarov, et Henri Orland, physicien à l'IPhT, vient de paraître chez Wiley. Félicitations Henri !

Un livre de François David

Un livre de François David

Un livre de François David, le tome 1 de la Théorie statistique des champs vient de paraître chez EDP Sciences dans la Collection Savoirs Actuels. Présentation de l'ouvrage: Les idées du groupe de renormalisation développées pour la physique statistique dans les années 1970, en grande partie grâce au prix Nobel de physique Kenneth Wilson, ont entièrement renouvelé ce que l’on appelait la théorie relativiste des champs quantiques, née dans les années 1930 et développée sous la forme de l’électrodynamique quantique dans les années 1950. Un résultat de ce renouvellement est la théorie statistique des champs, une boîte à outils de tout physicien théoricien, de la physique des hautes énergies à la physique statistique.

Philippe Brax (IPhT), representing UP Saclay in EuCAPT

Philippe Brax (IPhT), representing UP Saclay in EuCAPT

On July 10th, P2I-P2IO/UP Saclay became a part of EuCAPT and Philippe Brax represents Paris-Saclay in the Streering Committe

A Workshop on Astroparticles at the Institute Pascal

A Workshop on Astroparticles at the Institute Pascal

The Paris-Saclay AstroParticle Symposium 2019 has begun at the Institute Pascal The 2019 AstroPascal workshop on astroparticles is taking place place at the Pascal Institute of the Paris-Saclay University. It is organized by Philippe Brax of IPhT and Yann Mambrini of LPT-Orsay. Around 30 specialists of astrophysics, cosmology and particle physics will be invited to discuss and work on the themes: Dark Energy and Dark Matter. The format will be flexible enough to allow for strong interactions between participants. There will be working sessions every day and on Fridays, a « conference » format day with invited speakers. We have invited confirmed researchers and are strongly encouraging the presence of their students and/or postdocs. The ultimate aim is to initiate-continue-finalise research projects in a nice environment.

Bertrand Eynard lauréat du prix Claude Berthault (Prix de l'Institut de France)

Bertrand Eynard lauréat du prix Claude Berthault (Prix de l'Institut de France)

Bertrand Eynard est un physicien théoricien, qui après une thèse sur les matrices aléatoires (sous la direction de Jean Zinn-Justin), est devenu chercheur au CEA (Commissariat à l'énergie atomique et aux énergies renouvelables) depuis 1995. Ses travaux ont d'abord porté sur les matrices aléatoires où il a apporté d'importantes contributions et écrit et enseigné plusieurs cours. En 2004, il a introduit une nouvelle méthode algébrique pour le calcul du développement asymptotique des matrices aléatoires de grande taille, appelée la "récurrence topologique".

Lenka Zdeborovà is awarded the

Lenka Zdeborovà is awarded the "Young Woman Scientist" Irène Joliot-Curie Award 2018

We are pleased to learn that Lenka Zdeborovà, CNRS researcher at IPhT, has just been awarded the Irène Joliot-Curie "Young Woman Scientist" prize for the year 2018. The Irène Joliot-Curie Awards are intended to promote women's place in research and technology in France. They are awarded by the Ministry of Higher Education, Research and Innovation and Airbus with the support of the Academy of Sciences and the Academy of Technology. Lenka is interested in applications of methods developed in statistical physics, such as advanced mean-field methods, replica method and message passing algorithms, for problems in machine learning and artificial intelligence, signal processing, inference and optimization. In other words: what are the problems that can be solved effectively using a computer? If this question is traditionally addressed in the fields related to informatics, she approaches it from the point of view of statistical physics.

Quantum Field Theory : A book by François Gélis.

Quantum Field Theory : A book by François Gélis.

After having delivered for several years a course on quantum field theory at the Master program ¨High Energy Physics¨ at the Ecole Polytechnique, Francois Gelis's lecture notes have been published by Cambridge University Press in a volume entitled Quantum Field Theory: from basics to modern topics.

Qu’est-ce que la gravité ? A book by Philippe Brax, Etienne Klein and Pierre Vanhove

Qu’est-ce que la gravité ? A book by Philippe Brax, Etienne Klein and Pierre Vanhove

General relativity has just celebrated its centenary and the early detection of gravitational waves by LIGO and Virgo has confirmed Einstein's prediction that accelerated masses can produce an oscillation of space-time spreading at the speed of light.

24th Itzykson meeting: Effective Field Theory in Cosmology, Gravitation and Particle Physics, 5-7 juin 2019, IPhT

24th Itzykson meeting: Effective Field Theory in Cosmology, Gravitation and Particle Physics, 5-7 juin 2019, IPhT

Organizing commitee: Brando Bellazzini, John Joseph Carrasco and Filippo Vernizzi

Maxime Grandadam et Giuliano Giacalone, étudiants à l'IPhT, invités à l'émission

Maxime Grandadam et Giuliano Giacalone, étudiants à l'IPhT, invités à l'émission "La Recherche Montre en Main" de France-Culture

Maxence Grandadam, en thèse sous la direction de Catherine Pépin , a été invité le 12 décembre 2018 à l'émission quotidienne de France Culture "la méthode scientifique", dans sa rubrique dédiée aux doctorants "La Recherche montre en Main" au cours de laquelle ils doivent exposer en 4 mn le sujet de leurs recherches. Giuliano Giacalone, étudiant sous la direction de Jean-Yves Ollitrault, a également été invité à s'exprimer à cette émission le mercredi 30 janvier 2019. Emission La Recherche Montre en Main Interview de Maxence Grandadam

Maximal Supergravity at Five Loops !

Maximal Supergravity at Five Loops !

Single (top) vs double copy (bottom) theory This past year a team at IPhT around John Joseph Carrasco — in collaboration with physicists at UCLA and Penn State University in the United States, and Uppsala University in Sweden — completed a calculation long thought to be impossible: the direct understanding of the dimensions of space-time in which the most symmetric particle-based field theory of gravity (maximal supergravity) would cease to be predictive when quantum effects are relevant. One can isolate order by order the quantum effects in graviton scattering. For two gravitons scattering off of each other, this calculation required consideration of the fifth-order quantum correction. This puts strong constraints on the behavior of fundamental symmetries in controlling the high-energy behavior of this theory.

Shaking Strongly Correlated Electrons

Shaking Strongly Correlated Electrons

Periodically driven quantum many-body systems (such as cold atoms in time-dependent optical lattices and quantum materials under ultra-fast optical excitation) offer exciting perspectives of exploring quantum phases of matter along genuine non-equilibrium pathways.This so-called Floquet engineering relies, however, on the suppression of heating, i.e. the uncontrolled energy absorption from the drive. This was known to be the case only in the limit of extremely high frequency,thus limiting its practical use. A team at IPhT around Francesco Peronaci, Marco Schiro and Olivier Parcollet showed that also strong electronic interactions can largely circumvent energy absorption, and thus provide a robust platform for Floquet engineering even at finite frequency. This is demonstrated with non-equilibrium dynamical mean-field calculations on a driven Fermi-Hubbard model, a paradigmatic example of lattice correlated electrons.

Matière noire : la théorie des trous noirs disqualifiée

Matière noire : la théorie des trous noirs disqualifiée

Selon Miguel Zumalacarregui, de l'IPhT, et son collaborateur Uros Seljak, la matière noire ne peut être intégralement constituée de trous noirs de masse supérieure à un centième de la masse solaire. Il faut donc aussi chercher du côté des particules élémentaires pour démasquer la matière noire!

Giulio Biroli lauréat 2018 du Prix d'Aumale de l'Académie des Sciences

Giulio Biroli lauréat 2018 du Prix d'Aumale de l'Académie des Sciences

Le Prix d'Aumale (fondation de l'Institut de France), créé en 1866, est un prix annuel décerné sur proposition de chacune des cinq Académies. Il est décerné tous les 5 ans par l'Académie des Sciences. Les travaux théoriques de Giulio Biroli ont concerné de nombreux aspects de la physique statistique des milieux désordonnés, tels les verres ou les matériaux amorphes. Il a montré que ces milieux présentent des phénomènes de vieillissement caractéristiques du désordre. Dans ces phases, la théorie usuelle de l'élasticité est perdue.

Michel Gaudin recipient of the 2019 Dannie Heineman APS/AIP Prize for Mathematical Physics

Michel Gaudin recipient of the 2019 Dannie Heineman APS/AIP Prize for Mathematical Physics

We are happy to learn that Michel Gaudin has been awarded the 2019 Dannie Heineman Prize for Mathematical Physics, together with Bill Sutherland (U. of Utah) and F. Calogero (U. di Roma La Sapienza), for their "... profound contributions to the field of exactly solvable models in statistical mechanics and many body physics, in particular the construction of the widely studied Gaudin magnet and the Calogero-Sutherland, Shastry-Sutherland, and Calogero-Moser models." This prize was established in 1959 by the Heineman Foundation for Research, Educational, Charitable, and Scientific Purposes, Inc., and is administered jointly by the American Physical Society and the American Institute of Physics. It recognizes outstanding publications in the field of mathematical physics. Michel Gaudin entered CEA in 1956 and is one of the "grands anciens" of what is now IPhT.

ReNewQuantum: ERC Synergy Grant at the Interface of Mathematics and Theoretical Physics

ReNewQuantum: ERC Synergy Grant at the Interface of Mathematics and Theoretical Physics

Bertrand Eynard (IPhT) has been awarded an ERC Synergy grant, "Recursive and Exact New Quantum Theory", together with J.E. Andersen (QGM, Aarhus University, DK), B. Eynard (IPhT), Mr. Kontsevich (IHES, Bures-sur-Yvette) and M. Mariño (UNIGE, Geneva, CH). Two other IPhT researchers are involved in this project. The Synergy Grants aim to establish collaborations between several researchers in different institutes on a common program. The goal of the ReNewQuantun program is to build new foundations for quantum field theory, beyond perturbation theory, by using advanced geometric and topological methods (topological recursion, geometric recursion, resurgence theory, non-linear Riemann-Hilbert methods, Fukaya categories, topological string theories, mirror symmetry, etc.). This program should open new avenues for exploring the relations between gravitation and quantum mechanics, and for incorporating it into unified theories of fundamental interactions.

« A la recherche des neutrinos » un livre de A. Kouchner et Stéphane Lavignac

« A la recherche des neutrinos » un livre de A. Kouchner et Stéphane Lavignac

Stéphane Lavignac (IPhT) vient de publier avec Antoine Kouchner, directeur du laboratoire Astroparticule et Cosmologie de l’Université Paris-Diderot, un livre de vulgarisation sur les neutrinos : « A la recherche des neutrinos – messagers de l’infiniment grand et de l’infiniment petit », collection « Quai des Sciences », éditions Dunod. Dépourvus de charge électrique, dotés de masses très petites et interagissant très faiblement avec la matière, les neutrinos comptent parmi les particules élémentaires les plus mystérieuses. Introduits presque en catimini par Wolfgang Pauli en 1930, dans une tentative désespérée de sauver le principe de conservation de l’énergie, les neutrinos n’ont eu de cesse d’intriguer les physiciens.

Beyond Amplitudes’ Positivity and the Fate of Massive Gravity

Beyond Amplitudes’ Positivity and the Fate of Massive Gravity

The idea that physics at low energy, i.e. large distances, can be described in terms of light degrees of freedom alone is one of the most satisfactory organizing principle in physics, which goes under the name of Effective Field Theory (EFT). The effect of short-distance ultraviolet (UV) dynamics is systematically accounted for in the resulting infrared (IR) EFT by integrating out the heavy degrees of freedom, which generate an EFT built of infinitely many local operators. Yet, EFT’s are predictive even when the UV dynamics is unknown, because in practice only a finite number of operators contributes, at a given accuracy, to observable quantities. The higher the operator dimension, the smaller the effect at low energy. Remarkably enough, extra information about the UV can always be extracted if the underlying Lorentz invariant microscopic theory is unitary, causal and local.

L’universalité des matrices aléatoires: un article de Bertrand Eynard dans Pour la science

L’universalité des matrices aléatoires: un article de Bertrand Eynard dans Pour la science

"L'énigme des matrices aléatoires", un article paru dans Pour la Science (mai 2018) sur les Matrices Aléatoires, par Bertrand Eynard, physicien à l'IPhT. Bertrand est depuis de nombreuses années un spécialiste des matrices aléatoires, sujet qu'il a enseigné à plusieurs reprises, en master et dans des Ecoles Doctorales, comme celle des Houches. Les lois des matrices aléatoires sont des lois statistiques universelles que l'on retrouve partout : que ce soit dans les temps d'attente des bus et des métros, les voitures garées le long d'un trottoir, les arbres d'une forêt, les neurones, la bourse, les antennes de téléphonie mobile, mais aussi les résonances des noyaux atomiques, la théorie des cordes, la chromodynamique quantique, et même les nombres premiers...

Nick Warner awarded an ERC Advanced grant to work at IPhT

Nick Warner awarded an ERC Advanced grant to work at IPhT

Nicholas Warner, Professor of Physics, Astronomy and Mathematics at USC, has just been awarded an ERC Advanced grant to work at IPhT for the duration of this fellowship. Already a visitor and regular collaborator of IPhT, Nick will arrive January 2019 to work on his program "QBH Structure: The Quantum Structure of Black Holes and the Recovery of Information" with IPhT researchers. He will bring his creativity, his energy and his enthusiasm to the CEA and the whole theoreticians community on this fundamental and fast growing subject, at the interface between fundamental interactions, cosmology and quantum information! Congratulations and welcome, Nick!

"Morphogenesis of Spatial Networks": a book by Marc Barthelemy

"Provides the first comprehensive presentation of state-of-the-art knowledge about spatial networks" This book develops a morphodynamical approach of spatial networks with a particular emphasis on infrastructure networks such as streets, roads and transportation networks (subway, train). The author presents the mathematical tools needed to characterize these structures and how they evolve in time. The book discusses the most important empirical results and stylized facts, and will present the most important models of spatial networks. The target audience primarily comprises research scientists interested in this rapidly evolving and highly interdisciplinary field, but the book may also be beneficial for graduate students interested in large networks.

"Deconstructing the string landscape": A new ERC consolidator grant for Mariana Graña !

Mariana Graña of IPhT has been awarded an ERC consolidator grant for her project "Deconstructing the string landscape". Congratulations Mariana ! Despite its uniqueness, string theory has a “landscape” of effective partly phenomenological low-energy solutions with very different observable physics. The objective of her project is to "deconstruct" this landscape, and determine what parts of it can be promoted to consistent full-fledged string theory solutions, and what parts are inconsistent. It aims at understanding if the present geometrical landscape paradigm can be put on solid ground, or if more inventive alternatives such as “non-geometric landscape” have to be searched.

Do LIGO/VIRGO experiments put constraints on dark energy ?

Do LIGO/VIRGO experiments put constraints on dark energy ?

The recent observation of gravitational waves from a neutron star binary inspiral by LIGO/Virgo and its electromagnetic counterpart in the form of a gamma-ray burst implies that gravitational waves travel at the speed of light, with deviations smaller than a part over million billions. Two Letters, one by Filippo Vernizzi (IPhT) and the other by Miguel Zumalaccaregui (currently MSCA fellow at BCCP Berkeley and IPhT), recently published in Physical Review Letters and chosen for the Editors' Suggestion, show dramatic consequences of this experimental result for models of dark energy and modified gravity. In some of these theories, dark energy acts as a refractive media for the propagation of gravity and a large class of them is ruled by this observation. The papers explore the implications for many known models and present the most general scalar-tensor theory leaving the speed of gravity unaffected.

Programme PSI2 DARKMOD at IPhT & IAS

Programme PSI2 DARKMOD at IPhT & IAS

Dark Energy and Modified-Gravity cosmologies: DARKMOD from September 11, 2017 to October 6, 2017 The acceleration of the expansion of the Universe at low redshifts has not received a satisfactory theoretical explanation yet. The value of a possible cosmological constant remains a puzzle and alternative approaches, dark energy or modified gravity, are still being developed. In view of the future observations by galaxy surveys, such as EUCLID for instance, it is timely to gather experts on both the theoretical aspects of dark energy and modified gravity, together with phenomenologists and observers. This 4-week workshop will provide an opportunity to discuss most aspects of both dark energy and modified gravity, from their theoretical construction to their link with observational cosmology.

Boulder School 2017: Frustrated and Disordered Systems

Boulder School 2017: Frustrated and Disordered Systems

Our colleague Lenka Zdeborová co-organizes the Boulder Summer School 2017 on Frustrated and Disordered Systems, July 3-28, 2017. Giulio Biroli is one of the keynote invited lecturers. On of the main goals of this event is to bring to a broader physics audience the advanced mean-field methodology developed (in considerable part in IPhT) in the physics of disordered systems, such as the replica and cavity methods. Modern applications of these methods in soft-matter physics, jamming, but also computer science and biology will be also exposed.

Large deviations of a tracer in the symmetric exclusion process

Large deviations of a tracer in the symmetric exclusion process

A particle in a one-dimensional channel with excluded volume interaction displays anomalous single-file diffusion with fluctuations scaling as t^(1/4) in the long time limit. This phenomenon has been demonstrated in various experiments involving different types of physical systems such as zeolites, capillary pores, carbon nanotubes or colloids. On a one dimensional lattice, the Symmetric Exclusion Process, particles performing symmetric random walks and interacting by hard-core exclusion, is a pristine model of a single-file diffusion, amenable to quantitative analysis (Spitzer, 1970). At equilibrium, the variance of the position of a tagged particle has been calculated exactly by Arratia in 1983, and this result has been discussed since then in numerous theoretical papers, at various levels of physical intuition or mathematical rigor. However, the full distribution of a tagged particle and its higher cumulants (prone to experimental measurements) are not known. A rigorous work by S.

Langevin Prize for François Gélis

Langevin Prize for François Gélis

The French Physical Society has attributed the 2015´ Paul Langevin prize to François Gelis, for his work on quantum field theory in the strong field regime, and its applications to the non-equilibrium evolution of a quark-gluon plasma. Congratulations to him for wonderful work !

Duncan Haldane, Nobel laureate in Physics in 2016, was a visitor at IPhT

Duncan Haldane, Nobel laureate in Physics in 2016, was a visitor at IPhT

David Thouless, Duncan Haldane and Michael Kosterlitz have been awarded the Nobel Prize in Physics 2016 for their works on topological effects in condensed matter physics. Duncan Haldane is well-known in France. He spent four years at the Institute Laue-Langevin in Grenoble, from 1977 to 1981. During a visit to the IPhT in the early 1990s, he exposed some remarkable degeneracies of the spin chain which bears his name. This was the starting point of a collaboration with Denis Bernard, Michel Gaudin and Vincent Pasquier. To know more, please see the attached file : Haldane-en (pdf)

Does order exist in glasses ?

Does order exist in glasses ?

Glasses are ubiquitous in daily life and technology. However, the microscopic mechanisms generating this state of matter remain subject to debate: Glasses are considered either as merely hyperviscous liquids or as resulting from a genuine thermodynamic phase transition toward a rigid state. A team of theoreticians and experimentalists, including Giulio Biroli from IPhT, have devised an experiment based on new theoretical ideas to provide a smoking-gun answer to this long-standing controversy. Performing the corresponding high-precision nonlinear dielectric experiments for supercooled glycerol and propylene carbonate, they find strong support for theories based on thermodynamic amorphous order. Moreover, when lowering temperature, they find that the growing transient domains are compact; that is, their fractal dimension df = 3.

New book «Counting Surfaces» by Bertrand Eynard

New book «Counting Surfaces» by Bertrand Eynard

The book "Counting Surfaces" by Bertrand Eynard just appeared in the collection "Progress in Mathematical Physics" by Birkhäuser. In 2015 Bertrand Eynard was the recipient of the Chaire André Aisenstadt at CRM Montréal and gave courses to present his recent results. This book is published in connection with these courses. It presents the general theory of the enumeration of maps, of the counting of Riemann surfaces, its combinatorics, geometrical and topological aspects, and its connection with physics and mathematics (string theory, random matrix theory, algebraic geometry, integrable systems, topological recursion). This book is self contained and aims at graduate students as well as advanced researchers. It should hopefully become quickly a classic!

21st Claude Itzykson Conference

21st Claude Itzykson Conference "Dynamics, Disorder and Localization in Strongly Interacting Quantum Many Body Systems”

The 21st edition of this conference will take place on June 13-15 at IPhT. It will be devoted to the themes of Dynamics, disorder and localization in strongly interacting quantum many body systems. It is organized by Giulio Biroli, Eugene Bogomolny, Cecile Monthus and Marco Schiro, with the help of Sylvie Zaffanella, Anne Angles, Laure Sauboy (secretary). For registration, list of speakers, program and practical info, see the web site ot the conference.

Catherine Pépin is awarded an Advanced Grant from the European Research Council

Catherine Pépin is awarded an Advanced Grant from the European Research Council

Catherine Pépin, permanent physicist at IPhT, has just been awarded a prestigious Advanced Grant from the European Research Council. This grant will enable her tu pursue, during five years, the exploration of charge orders and the SU(2) symmetry for understanding the phase diagram of cuprate superconductors. Congratulations to Catherine !

A Field Theory for String Theories ?

A Field Theory for String Theories ?

Since strings are one-dimensional objects, they have richer dynamics than point particles. There are many indications that this richness can be captured by a "double field theory", which is a field theory in a double-dimensional space. One of the stringy features that suggests this are winding states: modes where strings have a quantized wrapping number around compact cycles of the space, the simplest yet rich case being that of a circle. Winding modes have a mass proportional to the radius of the circle, while momentum states have a mass proportional to the inverse of the radius. There is a symmetry (T-duality) that interchanges these states while inverting the size of the circle. These two modes are nothing else than the harmonics of the doubled space. However, in order to make the double field theory consistent, a constraint is imposed, such that fields are independent of the T-dual coordinates, and no winding modes are allowed.

Prochaine conférence Cyclope donnée par Chiara Caprini, de l'IPhT, et Isabelle Grenier de l'Irfu le mardi 29 mars 2016 à 20h : Ondes gravitationnelles, les frémissements de l'espace-temps

Prochaine conférence Cyclope donnée par Chiara Caprini, de l'IPhT, et Isabelle Grenier de l'Irfu le mardi 29 mars 2016 à 20h : Ondes gravitationnelles, les frémissements de l'espace-temps

L’Unité communication du CEA Saclay a le plaisir de vous convier à sa prochaine conférence CYCLOPE. Pour rappel, ces conférences de vulgarisation scientifique, destinées à tous publics, sont gratuites et ont lieu sur le plateau de Saclay, à l’INSTN. Vous trouverez toutes les informations utiles dans l’invitation en pièce jointe.

From theoretical physics to artificial intelligence

From theoretical physics to artificial intelligence

The daily financial newspaper Les Echos devotes an article to a former PhD student of IPhT, Ekaterina Retinskaya-Besse, who joined the startup Dreamquark after her PhD (2014) and then founded Dreamup Vision which applies deep learning techniques to retina analysis. Congratulations Katya!

Devil staircases in dimer models

Devil staircases in dimer models

Dimer models appear in different fields of statistical physics (Ising models), in the theory of correlated electron systems (antiferromagnetic insulators and topological phases of matter), field theory (compactified free field) and combinatorics (partitions and "Aztec diamonds"). These models are built from arrangements of "rods" (dimers) that occupy the bonds of a lattice, and which satisfy a hard-core constrain: each lattice site must touch the end of one and only one dimer. In the quantum versions of these models, the dimers have the possibility to move on the lattice (hopping terms in the hamiltonian), and this leads to some rich quantum many-body models, but which study is in general difficult. In a recent work [1], some theoreticians (IPhT, Paris-Sud University and P. et M.

Conference

Conference "de Sitter and microstate lansdscapes in string theory"

The conference "de Sitter and microstate lansdscapes in string theory" took place at IPhT from June 16 to 19, 2015. This workshop gathered 70 participants from around the world to discuss recent advances in understanding the landscapes of de Sitter spaces in string theory on one hand, and of black hole microstate geometries on the other. Both landscapes have experienced quite intense recent remodeling: on the black hole side this was driven by “fuzzball/firewall” information-theory-based arguments that black hole solutions are only thermodynamic approximations that stop describing the physics at the scale of the horizon, where they should be replaced by horizonless geometries dual to the black hole microstates, and on the cosmology side by the realization that antibranes, which are one of the key ingredients needed to obtain a landscape of de Sitter vacua, may give rise to instabilities.

Romain Vasseur receives a PhD Prize from the

Romain Vasseur receives a PhD Prize from the "Triangle de la Physique"

Romain Vasseur, former graduate student at IPhT, has been awarded a 2015 PhD prize from the "Triangle de la Physique", in the category "Theory". Romain's PhD thesis, co-directed by Hubert Saleur (IPhT) and Jesper Jacobsen (LPTENS), is dealing with nonunitary Conformal Field Theories and various applications in condensed matter physics and geometrical models of statistical mechanics. Romain is now postdoc at UC Berkeley. Congratulations Romain!

Hubert Saleur receives an ERC Advanced Grant

Hubert Saleur receives an ERC Advanced Grant

Hubert Saleur, permanent physicist at IPhT, has just been awarded a prestigious Advanced Grant from the European Research Council. This grant will allow him to develop, during the 5 next years, his research project on the "plateau transition" in the Quantum Hall Effect, a famous unsolved problem in condensed matter physics. In this direction, he also aims at studying and classifying Nonunitary Conformal Field Theories. Congratulations Hubert!

Anomalous diffusion and fluctuations of a tracer particle

Anomalous diffusion and fluctuations of a tracer particle

Single-file diffusion is referred to the motion of many interacting particles in one-dimensional channel which are so narrow that the particles can not pass each other, and as a result their sequence is preserved over time. Since its introduction more than 50 years ago, in modelling ion transport through cell membranes, the single-file diffusion has been observed in a wide variety of systems, e.g. diffusion of large molecules in zeolites, carrier migration in super ionic conductors, sliding of proteins along DNA, and many more.The characteristic feature of single-file diffusion is that, the variance of the displacement of a tracer particle at a time much larger than the mean collision time, scales as the square-root of time, compared to the linear dependence in normal diffusion. This sub-diffusive scaling has been demonstrated in a number of experimental realization.

Bending of Light in Quantum Gravity

Bending of Light in Quantum Gravity

A century ago Albert Einstein used his new theory of gravity – the general relativity - for evaluating the bending angle of rays of light under the gravitational pull from the Sun. Ludovic Planté, Pierre Vanhove and their colleagues have evaluated for the first time the quantum gravity correction to this bending angle. The computation is done in the framework of the low-energy effective field theory, which allows evaluating large distance effects by keeping only low energy fields and couplings. This contribution is universal to any theory of quantum because since it is independent of (any unknown) high-energy degrees of freedom. The quantum correction depends on the spin of the deflected massless particle, in contrast to the classical contribution. Therefore it violates the equivalence principle but preserves the fundamental symmetries of the theory on which Einstein based his theory of general relativity. "Bending of Light in Quantum Gravity", N. E. J.

RNA: The unknotted strands of life

RNA: The unknotted strands of life

No one had checked before, but RNA, the nucleic acid involved in many cell functions including protein synthesis, appears to be the only « strand of life » not to have knots. Over the years, advances in structural biology have firmly established that both proteins and DNA, although subject to evolutionary selection, do not escape the statistical law whereby a sufficiently long and compacted molecular strand will inevitably be entangled. However, no one to date had looked into the case of RNA. Using the structural description provided for approximately 6,000 RNA chains entered in the Protein Data Bank, a team of researchers from the SISSA (Italy) and the IPhT has performed a thorough study of the presence of knots in these biopolymers.

Liouville Quantum Gravity on the Riemann Sphere

Liouville Quantum Gravity on the Riemann Sphere

In 1981, the famous theoretician A. Polyakov introduced the quantum Liouville theory as a model for the quantized string. This theory “quantizes” the Liouville equation R=-1 of classical geometry, which characterizes Riemann surfaces with negative curvature. It is thus a quantum theory of gravity, where the geometry of a two dimensional space-time in quantized (1 time dimension + 1 space dimension). Liouville theory has remarkable properties. It is a conformal theory (it is endowed with an infinite symmetry group, the same as for string theories and critical systems such as the Ising model in two dimensions). Liouville theory appears, sometimes unexpectedly, in many problems of theoretical physics and of pure mathematics. It has been therefore very much studied via the methods of Conformal Field Theory and of Integrable Systems.

A new, yet faster, version of FastJet

A new, yet faster, version of FastJet

Quarks and gluons are abundantly produced in the final state of the LHC collisions. They are observed as collimated showers of particles, known as jets. Jets are crucial objects in particle physics, used e.g. in about 60% of the LHC analyses. In practice, jets need to be reconstructed from the particles in the final state using a jet algorithm (the anti-kt algorithm [1] at the LHC). This, as well as all sorts of manipulations on jets --- e.g. calculating their area, subtracting soft contamination or studying their internal (sub)structure --- is done numerically. FastJet [2], developed by Matteo Cacciari, Gavin Salam and Gregory Soyez, is the computer interface used by the high-energy community to perform this fundamental task. With hundreds of events recorded every second at the LHC, time is of the essence.

Uncovering the spatial structure of mobility networks

Uncovering the spatial structure of mobility networks

The extraction of a clear and simple footprint of the structure of large, weighted and directed networks is a general problem that has many applications. An important example is given by origin-destination matrices, which contain the complete information on commuting flows, but are difficult to analyze and compare. Marc Barthelemy, and Thomas Louail, together with their collaborators proposed a versatile method [1], which extracts a coarse-grained signature of mobility networks, under the form of a 2x2 matrix that separates the flows into four categories. They applied this method to origin-destination matrices extracted from mobile phone data recorded in 31 Spanish cities and showed that these cities essentially differ by their proportion of two types of flows: integrated (between residential and employment hotspots) and random flows, whose importance increases with city size.

Spin Vertex and 3 Point Function in AdS/CFT Correspondence

Spin Vertex and 3 Point Function in AdS/CFT Correspondence

The gauge/string duality is a half-century old idea, which appeared as an attempt to give an adequate description of strongly correlated quantum field theories, such as QCD. The best studied example of such a duality, known by the name AdS/CFT, is the relation between the maximally supersymmetric multi-color Yang-Mills theory in four dimensions, the conformal invariant “super-QCD”, and a super-string theory in a ten-dimensional curved space, composed of a 5-dimensional anti-de Sitter (AdS) space and a 5-dimensional sphere. The dramatic progress of our understanding of AdS/CFT achieved in the last decade was triggered by the discovery that both sides of the correspondence possess the same integrable structure of the type usually associated with two-dimensional systems, as the Heisenberg XXX ferromagnet. AdS/CFT gives the first example of a non-trivial 4-dimensional integrable theory.

Hélène Dupuy receives a

Hélène Dupuy receives a "L'Oréal - UNESCO for women in science" fellowship

Hélène Dupuy, 3d year graduate student in cosmology at IPhT, under the supervision of Francis Bernardeau, was awarded a L'Oréal - UNESCO "For women in Science" fellowship 2014. Every year, these fellowships are awarded in France to 10 outstanding graduate students, from all scientific domains, in order to support their research activities, as well as encourage outreach actions. Our warm congratulations to Hélène!

Roger Balian and François David interviewed on quantum physics

Roger Balian and François David interviewed on quantum physics

In December 2013, we interviewed two of our eminent scientists, Roger Balian and François David, about the foundations of quantum mechanics. We have used the 17 questions ( educed to 15) of Maximilian Schlosshauer in his book "Elegance and Enigma: The Quantum Interviews" in order to set up a context in which to ask the questions. The result is a movie that you can watch on this site or on YouTube. Enjoy the show ! https://www.youtube.com/watch?v=-K_8W9lnSp8 For more information: Understanding quantum measurement from the solution of dynamical models, A. Allahverdyan, R. Balian, T. Nieuwenhuizen, Physics Reports 252 (2013) p. 1-166 The Formalisms of Quantum Mechanics, an introduction, F. David, Lecture Notes in Physics Vol. 893 (Springer 2015)

Robi Peschanski on air on France Culture

Robi Peschanski on air on France Culture

Our Colleague and friend Robi Peschanski was interviewed last Saturday on the radio station France Culture as part of the series of “Scientific conversations” held each Saturday by Etienne Klein. Robi answered the question “In theory, what are looking for?” in this 45 minute long programme during which he has recalled snippets from his personal life and presented some of the major landmarks of particle physics from the 1960’s to the present time. You can download the interview following the link: http://www.franceculture.fr/emission-la-conversation-scientifique

Marco Cirelli awarded the Thibaud Prize of the académie de Lyon

Marco Cirelli awarded the Thibaud Prize of the académie de Lyon

Marco Cirelli has been awarded the Thibaud Prize given by the “académie des sciences, belles lettres et arts” of Lyon (France) for his work on Dark Matter and its indirect detection. This prize is attributed to a physicist, aged between 30 and 40, for his/her significant contributions to nuclear physics, particle physics or their applications to astrophysics. The ceremony will take place in Lyon on the 16th of December. We warmly congratulate Marco for this award!

The CRM invites Bertrand Eynard on an Aisenstadt Chair

The CRM invites Bertrand Eynard on an Aisenstadt Chair

Bertrand Eynard has been nominated by the Centre de Recherches Mathématiques (CRM) in Montreal on an Aisenstadt Chair, for the second semester 2015, related with the thematic semester devoted to the topics AdS/CFT, Holography, Integrability. This Chair will give him the opportunity to give a series of lectures on his work, and to write a monography, jointly published by the CRM and the American Mathematical Society. Since their creation in the 1970', the Aisenstadt Chairs have welcome the the CRM the most prestigious mathematicians. Bertrand has been a permanent member of IPhT since 1995. He has worked on the theory of random matrix models. Together with his former student Nicolas Orantin, he has developed the method of "topological recurrence", which has since then spread into various domains of mathematics (knot theory, geometry of Riemann surfaces, algebraic geometry) and theoretical physics (integrable systems, topologocal string theory..).

The CNRS Médaille de Bronze awarded to Lenka Zdeborova

The CNRS Médaille de Bronze awarded to Lenka Zdeborova

Lenka Zdeborova is the recipient of the CNRS "médaille de bronze" 2014 Congratulations! Chargé de Recherche at CNRS and member of IPhT since 2010, Lenka is a specialist of the statistical physics of complex systems and its applications in computer science and technology. The CNRS "médaille de bronze" is awarded in each scientific section of CNRS once a year to an exceptional young researcher.

A de Sitter landscape?

A de Sitter landscape?

String Theory has a “landscape” of solutions (space-time vacua) with negative cosmological constant (anti-de Sitter spaces) while fairly recent observations tell us that our universe undergoes an accelerated expansion, hence has a positive cosmological constant, corresponding to a de Sitter space. Obtaining such de Sitter spaces remains one of the major open problems in string theory. The most generic proposal starts from any solution in the landscape of anti-de Sitter vacua, and argues that one can transform it into a long-lived metastable de Sitter space by placing appropriate branes (extended dynamical objects that generalizes particle and strings). This mechanism gives rise to a huge landscape of string theory de Sitter vacua. I. Bena, M. Graña and collaborators at IPhT have shown that taking into account the dynamics of the branes always makes the solution singular, which invalidates the whole mechanism.

IPhT Activity Report 2008-2013

IPhT Activity Report 2008-2013

The activity report of IPhT, over the period January 2008 - June 2013, is now accessible online.

First consistent code to compute intrinsic non-Gaussian features in the cosmic microwave background

First consistent code to compute intrinsic non-Gaussian features in the cosmic microwave background

Zhiqi Huang and Filippo Vernizzi have developed at IPhT the first consistent numerical code to compute second-order effects in the cosmological perturbations and, in particular, the intrinsic non-Gaussian features expected in the cosmic microwave background temperature anisotropies. The cosmic microwave background is Gaussian to very high accuracy but there may be tiny deviations from a pure Gaussian distribution, that are remnants of certain models of the early universe. For this reason, one of the primary goals of the Planck satellite mission was to measure these deviations. Nevertheless, the signal coming from the early universe is always biased by non-linearities due to gravity and fluid dynamics, which must be fully understood to correctly interpreting the data. The numerical code developed at IPhT completely characterizes these nonlinearities and allows to filter out the primordial signal.

Super Yang-Mills, N=4, Integrability and Tests of the AdS/CFT Correspondence

Super Yang-Mills, N=4, Integrability and Tests of the AdS/CFT Correspondence

The supersymmetric gauge theory with maximal supersymmetry (SYM N=4) in four dimensions is a non-trivial quantum field theory which shares some of its main features with Quantum Chromo-Dynamics (QCD), the theory of strong interactions. Although QCD is only approximately scale invariant at high energy, the maximally supersymmetric theory is exactly scale invariant and endowed with an even larger symmetry: conformal invariance. Moreover, according to Maldacena’s conjecture of 1997, this theory is strictly equivalent to string theory on a space-time with neagtive curvature (the AdS5xS5 background). Moreover, in the ‘t Hooft planar limit where the number of quark colours becomes infinite, the theory becomes integrable with an infinite of non-local conserved charges. For all these reasons, the maximally supersymmetric Yang-Mills theory has been a very active subject in theoretical physics for the last decade.

"Journal of Physics A" : Best Paper Prize 2013

Since 2009, Journal of Physics A has awarded a Best Paper Prize, which serves to celebrate and applaud well written papers that make a significant contribution to their field. Among the winners for this year's Best Paper Prize are Gaëtan Borot (then on leave from IPhT, presently at MPI, Bonn) and Céline Nadal (Oxford) for their article "Purity distribution for generalized random Bures mixed states".

David Kosower receives the J. J. Sakurai Prize for Theoretical Particle Physics 2014

David Kosower receives the J. J. Sakurai Prize for Theoretical Particle Physics 2014

David Kosower was awarded the J. J. Sakurai Prize for Theoretical Particle Physics 2014, jointly with his collaborators Zvi Bern and Lance Dixon, "for pathbreaking contributions to the calculation of perturbative scattering amplitudes, which led to a deeper understanding of quantum field theory and to powerful new tools for computing QCD processes." The J. J. Sakurai Prize for Theoretical Particle Physics is awarded each year by the American Physical Society, to recognize and encourage outstanding achievement in particle theory. Congratulations!

Medaile Akademie věd ČR udělené v roce 2013 Rogeru BALIANOVI

Medaile Akademie věd ČR udělené v roce 2013 Rogeru BALIANOVI

Předseda Akademie věd ČR udělil v roce 2013 tyto medaile: Čestnou medaili AV ČR „De scientia et humanitate optime meritis“ prof. Rogeru BALIANOVI, z Institut de Physique Théorique, Saclay, France

The Mergier Bourdeix Prize is awarded to Pierre Vanhove

The Mergier Bourdeix Prize is awarded to Pierre Vanhove

The 2013 Mergier Bourdeix Prize has been jointly awarded to Sylvia Serfaty, Professor of Mathematics at the Université Pierre et Marie Curie, Paris, and to Pierre Vanhove, Physicist at IPhT, CEA Saclay. The Mergier Bourdeix Prize is one of the Grands Prix de l'Académie des Sciences: "It is awarded every year to a young French researcher working on fundamental scientific problems not directed towards immediate applications, and whose results reveal an exceptional talent. Pierre Vanhove mostly works on string theory.

A new algorithm for discrete tomography

A new algorithm for discrete tomography

X-ray tomography is a widely used imaging technique that allows one to produce internal images in materials science or medical applications. An X-ray beam is transmitted through the sample and the projection is recorded on a detector at different angles. The most widely used reconstruction algorithm of the original image from these measurements provides satisfying results only for a large number of such projections. In order to reduce the acquisition time or the total dose absorbed by the patient, tomography users need other reconstruction algorithms that incorporate known properties of the original image. In particular, images with a discrete set of absorption values and few interfaces are frequently encountered in materials science. Inspired by results from statistical physics of the Ising model, Lenka Zdeborova and her colleagues [1] have proposed a novel message-passing algorithm for discrete tomography.

Scaling laws for products of random matrices

Scaling laws for products of random matrices

Matrix products provide a natural tool to investigate one-dimensional systems consisting of many units in series, as soon as every unit can be described by means of a transfer matrix. Disordered systems usually yield products of independent random matrices which do not commute among themselves. Many situations of interest are already described by the simplest non-trivial case of 2 times 2 matrices. Typical examples include the Anderson problem of an electron propagating in a random potential, and classical and quantum Ising spin chains with random fields and/or exchange couplings. Furthermore, the most relevant quantities (localization length, density of states, free energy, ground-state energy) can be expressed in terms of the Lyapunov exponent characterizing the exponential growth of the matrix product with the number of factors.

Spin Imbalance and Spin-Charge Separation in a Mesoscopic Superconductor

Spin Imbalance and Spin-Charge Separation in a Mesoscopic Superconductor

What happens to spin-polarised electrons when they enter a superconductor ? Superconductors at equilibrium and at finite temperature contain both paired particles (of opposite spin) in the condensate phase as well as unpaired, spin-randomised quasiparticles. Injecting spin-polarised electrons into a superconductor thus creates both spin and charge imbalances. These must relax when the injection stops, but not necessarily over the same timescale. These different relaxation times can be probed by creating a dynamic equilibrium between continuous injection and relaxation, which leads to constant-in-time spin and charge imbalances. These scale with their respective relaxation times and with the injection current. Spin-charge separation effects could occur e.g. if the spin relaxation time is longer than the charge relaxation time. In a recent article published in Nature Physics [1], C. Bena et al. present evidence for an almost-chargeless spin imbalance in a mesoscopic superconductor.

Cookbook for Dark Matter Indirect Detection

Cookbook for Dark Matter Indirect Detection

Marco Cirelli and his collaborators (mostly based at CERN, in Estonia and in Italy) had published back in 2010 a complete set of numerical products for Dark Matter Indirect Detection. This work is increasingly used by the community and it is becoming, for some aspects, the state-of-the-art set of tools for this domain. Since several decades, cosmological and astrophysical evidence accumulate on the existence of Dark Matter (DM), thanks to its gravitational influence at different scales, showing that it constitutes 80% of the matter in the Universe. On the other hand, an explicit (non- gravitational) manifestation of DM is yet to be identified as its nature is as elusive as ever. One of the most promising approaches to solve this mystery is Indirect Detection, which aims to unravel the possible excess in cosmic rays produced by the annihilations or decay of DM particles in the Galaxy or beyond.

Roger Balian is 80!

Roger Balian is 80!

One of the founders of the Service de Physique Théorique de Saclay in the early sixties, Roger Balian is still one of its most eminent members. Head of the SPhT from 1979 to 1987, member of the French Académie des Sciences, former student and Professor at Ecole Polytechnique, former Director of the Les Houches Physics School, he authored well known teaching books. Roger is famous for the Balian-Low theorem, the Balian-Bloch semiclassical expansions, the discovery of the B-Phase of superfluid He3, his works in nuclear physics and the N-body problem, on the Casimir effect, on irreversibility and entropy in statistical mechanics, etc. As active as ever, Roger is presently interested in the measurement process in quantum mechanics. Happy birthday Roger!

Apprivoiser les statistiques hors d'équilibre

Apprivoiser les statistiques hors d'équilibre

Alexandre Lazarescu, Kirone Mallick et leurs collaborateurs ont publié dans Physical Review Letters une caractérisation analytique de la statistique du courant dans un modèle simplifié de transport classique (le processus d'exclusion asymétrique) loin de l’équilibre thermodynamique. Ce résultat constitue un véritable tour de force mathématique dans un domaine où les solutions exactes sont rares. Le processus d'exclusion, étudié depuis plus de 40 ans dans des disciplines scientifiques variées (théorie des probabilités, physique statistique, biophysique) propose un cadre d’étude précis des relations entre les descriptions microscopique et macroscopique d'un système non-thermodynamique.

"Journal of Physics A" : Best Paper Prize 2012

Since 2009, Journal of Physics A has awarded a Best Paper Prize, which serves to celebrate and applaud well written papers that make a significant contribution to their field. Among the winners for this year's Best Paper Prize are Kirone Mallick et Alexandre Lazarescu for their article "An exact formula for the statistics of the current in the TASEP with open boundaries".

Great success for the 17th annual meeting Itzykson!

Great success for the 17th annual meeting Itzykson!

The 17th edition of the Itzykson meeting took place in IPhT on June 18-20 2012, and was devoted to dark energy and modified gravity. This is a topical subject in cosmology nowadays, as testified by the 2011 Nobel prize in physics which has been awarded to the discovery of the acceleration of the universe Displays meetings Twenty-six speakers coming from all over the world have presented the most recent advancement in dark energy and modified gravity both from the observational and the theoretical point of view: on one side, the forthcoming observational dark energy surveys have been presented, such as Euclid and Wiggle-Z, which will allow an extremely precise measurement of the properties of cosmic acceleration; on the other side, the latest theoretical proposals for modifying gravity have been debated, such as massive gravity, chameleons and galileons theories.

Permanent Position in Theoretical Physics

Permanent Position in Theoretical Physics

The IPhT invites applications for a permanent research position in Particle physics beyond the Standard Model at the advanced junior to senior faculty level. More informations can be found on http://ipht.cea.fr/en/Phocea-SPhT/ast_visu_spht.php?id_ast=643

17th Itzykson meeting

17th Itzykson meeting

This year the 17th Itzykson meeting will be devoted to Dark Energy and Modified Gravity. It will be held in the amphi Bloch on June 18-20. You are all invited to participate. If you plan to attend the full three days, please register on the website. This will help us to keep track of the total number of participants. Thank you! We hope to see you there, Philippe, Chiara and Filippo

"Nuclear Physics B" award

Gregory Korchemsky has received an award from the journal "Nuclear Physics B" for his 2008 paper entitled "Conformal properties of four-gluon planar amplitudes and Wilson loops", which is one the most cited article in this journal for the period 2006-2010. NPB_topcited_Korchemsky.pdf (350 Ko)

ERC grant for

ERC grant for "New Directions in Dark Matter Phenomenology at the TeV scale"

Marco Cirelli has just obtained an ERC Starting Grant of 5 years for his project "New Directions in Dark Matter Phenomenology at the TeV scale". The NewDark project focuses on the phenomenology of Dark Matter, particles which constitute 80% of the matter in the Universe (as many astrophysical and cosmological observations now confirm) but have never been discovered directly. The next few years will bring a large amount of data (from cosmic ray observations, gamma ray telescopes, underground nuclear recoil experiments and the Large Hadron Collider at CERN) thoroughly exploring for the first time the TeV scale, where the Dark Matter particles are expected to hide. The project aims at making the most of these data, addressing the issue from different complementary directions by combining particle physics theory, cosmology and astrophysics.

ERC grant for

ERC grant for "Non Perturbative Renormalization Group Theory of Glassy Systems"

Giulio Biroli obtained an ERC Starting Grant of 5 years for his project “Non Perturbative Renormalization Group Theory of Glassy Systems”. Glassy systems are central in several fields from statistical mechanics and soft matter to material sciences and biophysics and they appear even in completely different areas of science such as information theory, computer science, agent-based models and game theory. The aim of this ERC project is to develop a new, possibly groundbreaking, approach to glassy systems based on the non-perturbative renormalization group (NPRG) formalism. I will mainly focus on the problem of the glass transition and the physics of glass-forming liquids. It is likely that the progress we will make in this direction will also be instrumental also for other glassy systems such as spin glasses, quantum glasses and jamming systems.

"Nuclear Physics B" award

Marco Cirelli has received an award from the journal "Nuclear Physics B" for his 2009 paper entitled "Model-independent implications of the e+, e-, anti-proton cosmic ray spectra on properties of Dark Matter", which is one the most cited article in this journal for the period 2006-2010. prix-Cirelli.pdf (332 Ko)

Une bourse ERC pour étudier les systèmes quantiques fortement corrélés

Une bourse ERC pour étudier les systèmes quantiques fortement corrélés

Olivier Parcollet a obtenu une bourse ERC Junior (Starting Grant) de 5 ans pour son projet "Quantitative approaches for strongly correlated quantum systems in equilibrium and far from equilibrium."

Médaille d'argent

Médaille d'argent

Hubert Saleur reçoit la médaille d'argent 2011 du CNRS.

LabEx

Les résultats de l'appel à projets Laboratoires d'Excellence (LabEx) ont été annoncés le 25 mars 2011. Voici les décisions concernant les trois LabEx dans lesquels l'IPhT était impliqué : - labex « FMJH » (Fondation mathématique Jacques Hadamard) : non accepté - labex « P2IO » (Physique des 2 Infinis et des Origines) : accepté - labex « PALM » (Physique, Atomes, Lumière, Matière) : accepté

Attribution d’une chaire Blaise Pascal à Constantin Efetov sur l'IPhT

Attribution d’une chaire Blaise Pascal à Constantin Efetov sur l'IPhT

Financées par l’Etat et le Conseil régional d’Ile-de-France, les chaires Blaise Pascal donnent à un laboratoire francilien la possibilité d’inviter un scientifique de haut niveau pour participer à ses programmes. Constantin Efetov vient renforcer le groupe de matière condensée de l'IPhT. Les chaires internationales de recherche Blaise Pascal ont été créées en 1996 par l'Etat et la Région d'Ile-de-France. Chaque chaire permet à un scientifique étranger de très haut niveau et de renommée internationale de poursuivre ses travaux dans un établissement d'enseignement supérieur ou de recherche de Paris/Ile-de-France pendant 12 mois éventuellement répartis sur 2 ans. Les dossiers sont initiés et portés par le laboratoire invitant.

16ème Conférence ITZYKSON

16ème Conférence ITZYKSON

La 16ème conférence Itzykson sur le thème "Extremes and Records", organisée par C. Godrèche, S.N. Majumdar et G. Schehr, aura lieu du 14 au 17 juin 2011 à l'IPhT Saclay. Pour de plus amples renseignements, veuillez consulter le site : http://lptms.u-psud.fr/workshop/itzykson16/

Jean Zinn-Justin élu à l'Académie

Jean Zinn-Justin élu à l'Académie

Jean Zinn-Justin vient d'être élu membre de l'Académie des Sciences. C'est une juste reconnaissance de ses contributions majeures à la physique, en particulier à la théorie des champs. Je le félicite chaleureusement au nom de tout l'IPhT. Michel Bauer.

"Gay Lussac/Humboldt" 2010 prize to Volker Schomerus

We have learned that our former collegue Volker Schomerus, nominated by Hubert Saleur and Henri Orland, was awarded the Franco-German "Gay Lussac/Humboldt" 2010 prize. Volker Schomerus, is presently head of the theory group at the Deutsches Elektronen-Synchrotron DESY. Volker Schomerus was a permanent physicist at IPhT from 2002 to 2005 and is currently working in strings theory and quantum field theory.

Matt Luzum receives the Dissertation in Nuclear Physics Award from APS

Matt Luzum receives the Dissertation in Nuclear Physics Award from APS

<p><a href="/Phocea/file.php?reload=1288867805&class=newsImg&file=_316_0_.jpg"><img style="border: 0; margin: 0 8px 5px 0;" src="/Phocea/file.php?reload=1288867805&class=newsImg&file=_316_0_.jpg" alt="img" width="120" align="left" /></a>Matthew Luzum has received the 2011 Dissertation in Nuclear Physics Award from the Division of Nuclear Physics of The American Physical Society for "pioneering developments in the theory of relativistic viscous hydrodynamics, in particular for the implementation of stable numerical simulations that have been used to quantify the low value of the shear viscosity coefficient observed in ultrarelativistic heavy ion collisions at RHIC, with important implications for the near-perfect fluidity of the quark-gluon plasma." <br /> Matt earned his PhD from the University of Washington (Seattle) in 2009.

Une bourse ERC Senior pour la QCD

Une bourse ERC Senior pour la QCD

<a href="/Phocea/file.php?reload=1287841817&class=newsImg&file=_313_0_.jpg"><img src="/Phocea/file.php?reload=1287841817&class=newsImg&file=_313_0_.jpg" alt="img" style="border:0;margin:0 8px 5px 0;" align="left" width="120" /></a><p> </p> <p>Jean-Paul Blaizot vient d'obtenir une bourse ERC Senior.<br />Son projet s'intitule "Strongly coupled QCD matter" et durera 5 ans.<br /><br />Toutes les félicitations de l'IPhT.</p>

Une bourse ERC pour etudier les nanotubes de carbone et le graphène

Une bourse ERC pour etudier les nanotubes de carbone et le graphène

<p><a href="/Phocea/file.php?reload=1287841662&class=newsImg&file=_312_0_.jpg"><img style="border: 0; margin: 0 8px 5px 0;" src="/Phocea/file.php?reload=1287841662&class=newsImg&file=_312_0_.jpg" alt="img" width="120" align="left" /></a></p> <p>Cristina Bena a obtenu une bourse ERC Junior (Starting Grant) de 5 ans pour son projet "Understanding the Electronic Properties of Carbon Nanotubes and Graphene as Quantum Conductors".</p> <p><br />Cristina est enseignante-chercheuse à l'Université d'Orsay.  Grâce à  une chaire CEA - Université, l'IPhT peut l'accueillir à temps partiel.</p> <p>Avec toutes les félicitations de l'IPhT.</p>

ERC grant for

ERC grant for "The Low Energy Limit of String Theory and the Observable World"

It's official! Mariana Graña has obtained a 5 years "Starting Grant" of the European Research Council for her project "The Low Energy Limit of String Theory and the Observable World". Five other laureates for this third round of the ERC Starting Grant program are affiliated to the Direction des Sciences de la Matière. Congratulations to all !

CNRS

Lenka Zdeborová just got a "Chargée de Recherche" permanent research position at CNRS and will be a member of our Institute. Lenka is a specialist of the statistical physics of disordered systèmes, especially of combinatorial optimization. Lenka will renforce the group of statistical physics and condensed matter and we are very happy to welcome her at IPhT. H. Orland

2010 Beg Rohu Summer School "Concepts and Methods of Statistical Mechanics"

2010 Beg Rohu Summer School "Concepts and Methods of Statistical Mechanics"

<p><a href="/Phocea/file.php?reload=1263466896&class=newsImg&file=_252_0_.jpg"><img style="border:0;margin:0 8px 5px 0;" src="/Phocea/file.php?reload=1263466896&class=newsImg&file=_252_0_.jpg" alt="img" width="120" align="left" /></a>The 2010 Beg Rohu summer school of statistical physics and condensed matter "Concepts and Methods of Statistical Mechanics" will take place from the 23rd of August to the 4th of September 2010, at the French National Sailing School, on the peninsula of Quiberon in southern Brittany, France.</p> <p>Lectures:</p> <p>G. Biroli: Statistical Dynamics<br /> J.-S. Caux: Integrable Models in Atomic and Condensed Matter Physics<br /> B. Delamotte: Non-Perturbative Renormalization Group<br /> W.

PhD proposals at IPhT in 2010

PhD proposals at IPhT in 2010

<p><a href="/Phocea/file.php?reload=1261051945&class=newsImg&file=_250_0_.jpg"><img style="border:0;margin:0 8px 5px 0;" src="/Phocea/file.php?reload=1261051945&class=newsImg&file=_250_0_.jpg" alt="img" width="80" align="left" /></a>IPhT scientists propose PhD topics for 2010. Subjects include: string theory, QCD physics, statistical physics, out of equilibrium systems. For the list of topics, possible fundings and administrative information, <a href="/Phocea-SPhT/ast_visu_spht.php?id_ast=108">see here</a>.</p> <p>A presentation visit of the Institute is scheduled on the afternoon of the 12th of January, 2010.</p>

Prix de l'Académie des Sciences

Prix de l'Académie des Sciences

Le Prix thématique de sciences physiques Ernest Déchelle est remis à Olivier PARCOLLET, chercheur à l’Institut de physique théorique du CEA à Saclay, pour ses travaux de recherche fondamentale dans le domaine de la physique théorique de la matière condensée. Ces travaux portent sur la compréhension des mécanismes liés à la supraconductivité à haute température critique. Le Prix Ernest Déchelle est attribué tous les quatre ans.

CNRS : affectation de Gregory Soyez à l'IPhT

CNRS : affectation de Gregory Soyez à l'IPhT

<a href="/Phocea/file.php?reload=1261605909&class=newsImg&file=_223_0_.jpg"><img src="/Phocea/file.php?reload=1261605909&class=newsImg&file=_223_0_.jpg" alt="img" style="border:0;margin:0 8px 5px 0;" align="left" width="120" /></a><p> J'ai le plaisir de vous annoncer que Gregory Soyez, qui était candidat sur un poste CR2 à la commission 02 du CNRS, a été recruté et affecté dans notre laboratoire. Gregory est un spécialiste de QCD (physique des jets). Beaucoup d'entre nous le connaissent déjà, puisqu'il a été post-doc dans notre labo avant de partir à Brookhaven. Il a travaillé en particulier avec Robi, Edmond et Francois G. Nous lui souhaitons la bienvenue à l'IPhT.</p>

L'espace et le temps

L'espace et le temps

L'article "L'espace et le temps", paru dans ScintillationS, n°79 - Juin 2009, par Chiara CAPRINI. Espace-Temps.pdf (1.9 Mo)

Quantum fields in extreme environments

Quantum fields in extreme environments

A workshop to celebrate the 60th birthdays of Jean-Paul Blaizot and Larry McLerran will be held at IPhT, Saclay and IAP, Paris from April 23rd to 25th, 2009.

B. Eynard

A mini workshop on the work of B. Eynard and N. Orantin has taken place in december 2008 at the IPMU (Institute for the Physics and Mathematics of the Universe) inTokyo. It was devoted to the application of a topological recursion, recently discovered by B. Eynard and N. Orantin in the framework of random matrix theory, to topological string theory. More information : http://www.ipmu.jp

Henri Orland, président de la commission de Physique Statistique de l'IUPAP

Henri Orland, président de la commission de Physique Statistique de l'IUPAP

Depuis novembre 2008, Henri Orland est président de la commission C3-Physique Statistique de l'IUPAP(*). Il est également vice-président de l'IUPAP. (*) International Union for Pure and Applied Physics

Jean-Paul Blaizot obtient le prix J. Hans D. Jensen

Jean-Paul Blaizot obtient le prix J. Hans D. Jensen

L'Institut de Physique Théorique de l'Université Ruprecht-Karls d'Heidelberg vient de décerner à Jean-Paul Blaizot le prestigieux prix "J. Hans D. Jensen", pour ses travaux sur la chromodynamique quantique à température finie, le plasma quarks-gluons et le groupe de renormalisation exact.

Elle pense le monde en équations

Elle pense le monde en équations

Une interview de Géraldine Servant, physicienne de l'IPhT en détachement au CERN, par Les Quotidiennes, un site de la Tribune de Genève.

Chiara Caprini

<p><a href="/Phocea/file.php?reload=1226930371&class=newsImg&file=_164_0_.jpg"><img style="border:0;margin:8px;" src="/Phocea/file.php?reload=1226930371&class=newsImg&file=_164_0_.jpg" alt="img" width="80" align="left" /></a> Comme annoncé <a href="http://ipht-i.cea.fr/Phocea/Vie_des_labos/News/index.php?act=visu&id_news=137">en juillet 2008 </a><a href="http://ipht.cea.fr/Pisp/chiara.caprini/"> Chiara Caprini</a> a également pris ses fonctions de chercheur CNRS affectée à l'IPhT le 1er octobre 2008.

Filippo Vernizzi

Filippo Vernizzi

<p><a href="/Phocea/file.php?reload=1223042232&class=newsImg&file=_163_0_.jpg"><img style="border:0;margin:8px;" src="/Phocea/file.php?reload=1223042232&class=newsImg&file=_163_0_.jpg" alt="img" width="80" align="left" /></a>Dal primo di ottobre 2008, l'IPhT accoglie Filippo Vernizzi, con un posto di ricercatore in fisica permanente CEA. Specialista di cosmologia e di relatività generale, Filippo si è addottorato all'Università di Ginevra, ha poi lavorato a Parigi, ad Helsinki e, più recentemente, all'International Center for Theoretical Physics di Trieste. Farà parte del gruppo di cosmologia, e continuerà la sua ricerca sulla fisica dell'universo primordiale in relazione alla formazione di strutture a larga scala nell'universo. Gli auguriamo il benvenuto a Saclay.</p>

PRACE, Partnership for Advanced Computing in Europe

PRACE, Partnership for Advanced Computing in Europe

A la demande de DSM, Jean-Marie Normand s'est impliqué dans le projet européen PRACE (Partnership for Advanced Computing in Europe) qui s'étale sur la période 2008-2009. Seize pays sont maintenant engagés dans ce projet qui prépare la création d'un service pérenne transeuropéen de calcul de haute performance comportant trois à cinq centres équipés de système "Pétaflopique" (*) (plus d'un ordre de grandeur plus puissant que les systèmes actuellement disponibles) à l'horizon 2010, l'ensemble relié par des réseaux à très haut débit. L'objectif est de mettre à la disposition de la communauté scientifique et industrielle européenne des moyens de calcul au plus haut niveau mondial. Cette infrastructure sera gérée comme une seule entité avec soumission de projets de calcul à un comité d'experts. Le programme, impliquant des dizaines de millions d'Euros, est partiellement financé par le 7ème Programme Cadre Européen.

Marco Cirelli unveils PAMELA

Marco Cirelli unveils PAMELA

Two scientific reviews, Cosmos Magazine and Science News, are interested in Marco Cirelli's and Alessandro Strumia's work posted on the Arxiv physics website, relative to data received from PAMELA, a space observatory. cosmosmag.pdf (445 Ko) sciencenews.pdf (76 Ko)

The New York Times

The New York Times

When The New York Times is interested in the vitreous transition, and quotes Giulio Biroli's research. The complete article (97 Ko) in pdf.

David Kosower selected for an ERC Advanced Grant

David Kosower selected for an ERC Advanced Grant

David Kosower won an European Research Council grant, for his project " Modern Methods for Perturbative Gauge Theories". These grants are extremely competitive: in the domain Physical Sciences and Engineering only 105 candidates have been selected (13 from France, and only 2 from CEA, both at the DSM).

CNRS

Chers tous, Je viens d'apprendre que Chiara Caprini a été affectée par le CNRS dans notre laboratoire. Au nom de tout le laboratoire, je lui adresse toutes nos félicitations. Chiara renforcera le groupe de Cosmologie et Astro-Particules, et nous nous réjouissons tous de cette affectation. Bien amicalement, Henri

In memoriam Alexei Zamolodchikov

In memoriam Alexei Zamolodchikov

La conférence "Liouville Field Theory and Statistical Models" organisée à la mémoire d'Alexei Zamolodchikov, disparu prématurément le 19 octobre 2007, s'est déroulée du 21 au 24 juin 2008 à Moscou. Plusieurs chercheurs de l'IPhT participaient à cette manifestation, qui réunissait de nombreux amis et collègues d'Aliosha. Pour plus de détails voir ici et là .

Wonders of Gauge theory and Supergravity

Wonders of Gauge theory and Supergravity

Le site intranet de la DSM publie un article relatif à la conférence. http://www-dsmi.cea.fr/fr/actualites/merveilleuse_conference

European School ON GROWTH AND SHAPES

European School ON GROWTH AND SHAPES

The Enrage topical school "ON GROWTH AND SHAPES" consists of five introductory courses designated for PhD students and posdocs in physics and mathematics. The aim is a pedagogical presentation of basic concepts. At the end the audience should be well prepared to understand the current trends of research. It will take place in Paris at the Institut Henri Poincaré from June 2 to June 6, 2008. There will be ample time and space for discussions and interactions between the participants. It is followed by the 13th Itzykson Meeting PUZZLES OF GROWTH in Saclay

Workshop Disorder and localization phenomena 17-19 Mars

Workshop Disorder and localization phenomena 17-19 Mars

The website of the workshop DISORDER AND LOCALIZATION PHENOMENA, FROM THEORY TO APPLICATIONS (ENS and IHP, Paris Mars 17-19) has been updated (in particular, there is now the timetable of the courses). At this stage, we would like to ask you to signal to us if you plan to attend, as we hope very much (just send an email to one of the organizers). We are looking forward to seeing you at the workshop, The organizers, giacomin@math.jussieu.fr fltonine@ens-lyon.fr cecile.monthus@cea.fr

Geraldine Servant and Iosif Bena selected for ERC Starting Grants

Geraldine Servant and Iosif Bena selected for ERC Starting Grants

Two young physicists of IPhT, Geraldine Servant and Iosif Bena, have been selected under the first call for "Starting grants" launched by ERC(European Research Council): their projects are among the 431 which passed the quality thresholds for excellence, out of more than 9000 applications. Geraldine's project will be funded by ERC. It deals with the nature of dark matter and its manifestations. She will pursue her research at CERN. Iosif's project is on the reserve list of ERC, and will be funded by the French ANR. It deals with black holes and string theory.

PhD topics and Postdoctoral Positions 2008

PhD topics and Postdoctoral Positions 2008

PhD topics for 2008 are visible here Postdoctoral positions for 2008 are visible here

Friedrich Wilhelm Bessel Research Award

Friedrich Wilhelm Bessel Research Award

Our colleague Ruben Minasian has been elected the recipient of a Friedrich Wilhelm Bessel Research Award after having been nominated for this award by the German scientist Prof. Dr. Stefan Theisen, Max-Planck-Institut fuer Gravitationsphysik, Golm/Potsdam.

Activity report of SPhT

Activity report of SPhT

The activity report presents an overview of the activities of the Service de Physique Théorique (SPhT) from June 2005 to May 2007.

Alexei Zamolodchikov

Alexei Zamolodchikov

It is with a profound sadness that we learned yesterday morning of the decease of Alexei Zamolodchikov. Aliocha spent the year 2006 with us at SPhT, and we all appreciated very much his intelligence, his kindness and his warmth. We were all very happy that he was going to rejoin permanently our lab in the fall of 2008, after his return from Moscow. Aliocha was an immense physicist and the whole community of theoretical physics will miss him deeply. We present our deepest condolences to his family and friends. Henri Orland

Prix de l'Académie des Sciences

Prix de l'Académie des Sciences

Deux de nos collègues ont vu leurs travaux récompensés par des prix de l'Académie des Sciences. Il s'agit de Cécile Monthus, qui a reçu le prix Gustave Ribaud et de Ivan Kostov, qui a reçu le prix Servant, conjointement avec Vladimir Kazakov de l'ENS. Je leur adresse nos plus vives félicitations au nom de tout le SPhT.

Black Holes, Black Rings and Modular Forms

Black Holes, Black Rings and Modular Forms

Retrouvez sur le site de Saclay le reportage multimédia de François Legrand & Dominique Marchand pour DSM.tv. Le 37ième Institut d'été de Paris, organisé par Iosif Bena (SPhT, CEA), Boris Pioline (LPTHE & LPTENS, CNRS) & Gabriele Veneziano (Collège de France) a eu lieu le 24 août 2007.

Marco Cirelli

J'ai le très grand plaisir de vous annoncer que Marco Cirelli, qui est post-doc actuellement chez nous, a été affecté au SPhT comme CR2 par le CNRS. J'en suis très heureux et au nom de tous, je lui souhaite la bienvenue dans notre laboratoire. Henri Orland.

New students and postdocs

New students and postdocs

On September 3rd, let us welcome : Patrick DESROSIERS , postdoc Frank SAUERESSIG , postdoc Ki-Seok KIM , postdoc Ashish SAXENA , postdoc Kristian KENNAWAY , postdoc Marco SARACENO , visitor Jeanne PARMENTIER, graduate student Olivier MARCHAL , graduate student Clément RUEF , graduate student

Giulio BIROLI, Young Scientist Award of IUPAP

Giulio BIROLI, Young Scientist Award of IUPAP

Our colleague Giulio Biroli has received the prestigious "Young Scientist Award" of IUPAP International Union of Pure and Applied Physics), jointly with Tomohiro Sasamoto (Chiba University, Japan), for his groundbreaking works on glassy systems. This prize is awarded for the first time this year. H. Orland http://www.statphys23.org and http://www.stat.phys.titech.ac.jp

Christophe Grojean, 2006 Thibaud award winner

Christophe Grojean, 2006 Thibaud award winner

Our colleague Christophe Grojean has been awarded the 2006 Thibaud prize for his contributions to theoretical particle physics beyond the standard model.

SPhT Workshop

The SPhT Workshop takes place at La Rochelle, october 4-6, 2006. Invited participants: David Bensimon (LPS-ENS), Xavier Viennot (LaBRI-Bordeaux), François Daviaud (SPEC-CEA), Jean-Michel Raimond (LKB-ENS). Program: scientific talks, welcome session for new members and visitors, prospective discussion sessions.

Junior Faculty Position in Theoretical Physics

Junior Faculty Position in Theoretical Physics

The Theoretical Physics Department (SPhT) at CEA, Saclay invites applications for a permanent staff position in Theoretical Physics, at the junior faculty level. Candidates must have a PhD and postdoctoral experience. The position will be offered in one of the three following fields: Theoretical Cosmology, Perturbative Quantum Chromodynamics, Statistical physics of biological systems. The deadline for applications is September 15, 2006.

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