The center for Theoretical Physics (CPHT) at Ecole Polytechnique gathers research scientists working in diverse domains of fundamental and applied Physics. The overall coherence is assured by the corpus of common, transposable, mathematical and numerical methods.
CPHT is on the campus of Ecole Polytechnique, buildings 5 and 6. The reception offices are located in "building 6" , offices 06.1046 and 06.1045.
 

Postal Address :
CPHT 
Ecole Polytechnique 
91128 Palaiseau cedex 
France

Secretary phone number : 01 69 33 42 01 (from abroad: +33 169 334 201)

Write an email to someone at CPHT :  : firstname.lastname@polytechnique.edu

 

CPHT, Ecole Polytechnique, Salle de Conférence Louis Michel

Giuseppe Policastro (ENS)

Title: Quantum complexity and holography

Abstract: I will discuss the motivations for introducing the notion of quantum complexity in physics, coming from the issues related to the information loss paradox in black holes. I will introduce the definition of complexity, the different proposals for its holographic computation, its inherent ambiguity, then present the computation for the case of a boundary/defect CFT.

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Ridge, NY, 26 February 2020 — The American Physical Society (APS) has selected 147 Outstanding Referees for 2020 that have demonstrated exceptional work in the assessment of manuscripts published in the Physical Review journals. A full list of the Outstanding Referees is available online at http://journals.aps.org/OutstandingReferees.

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The Summer School will take place from July 7 to July 17 2020 at the Institut d'Etudes Scientifiques de Cargèse, located on the west cost of the beautiful Corsica island, nearby the city of Ajaccio.

The purpose of this Summer School is to train the next generation of young researchers in the field of quantum simulation and, more generally, quantum technologies. Grouping together a diverse community as well as young and leading senior researchers, we expect a stimulating cross-fertilization of ideas, methods, and approaches, able to further develop this fields beyond the present frontiers.

Information about the Summer School, including a list of speakers and application forms can be found on the website: 
https://quantsim2020.sciencesconf.org

Important dates
Opening of applications: Mon, 24 Feb 2020
Deadline for application: Fri, 20 March 2020
Notification of acceptance: Mid-April
Deadline for registration: Mon, 15 May 2020

Organizers 
Thierry Giamarchi, Giacomo Roati, and Laurent Sanchez-Palencia

 

 

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Silke Biermann, Présidente du Département de Physique à l'Ecole Polytechnique, Professeur à l'Ecole Polytechnique et chercheuse au Centre de Physique Théorique, s'est vue décerner la médaille d'argent du CNRS pour ses travaux développant des approches de calculs de structures électroniques pour les matériaux corrélés à partir de premiers principes.

La médaille d'argent distingue des chercheurs et des chercheuses pour l'originalité, la qualité et l'importance de leurs travaux, reconnus sur le plan national et international.

English

 

THURSDAY 13 FEBRUARY, 2 p.m.  SALLE LOUIS MICHEL

BALT VAN REES

QANTUM FIELD THEORY in ANTI-DE SITTER and the S-MATRIX

Abstract:
We discuss results obtained by considering gapped QFTs in a fixed Anti-de Sitter background. Much like in the AdS/CFT correspondence, we can naturally define
'boundary' observables that exhibit conformal invariance in one dimension less. These observables can be analyzed using conformal bootstrap techniques which results in new non-perturbative bounds on the strength of the coupling constants in a general QFT. When we send the AdS curvature to zero the boundary observables should morph into the S-matrix of the flat-space QFT. We will discuss the different ways in which this connection can be made explicit, and how it might end up teaching us new lessons about the non-perturbative structure of scattering amplitudes.

THURSDAY 13 FEBRUARY, 3.15 p.m.    SALLE LOUIS MICHEL

JÜRG FRÖHLICH

THE FOURTH PILLAR which QUANTUM MECHANICS RESTS UPON

Abstract:
Traditionally, the three concepts of states, observables and unitary evolution form the pillars Quantum Mechanics is built upon. It is well known that they do not suffice to solve, for example, the so-called measurement problem.
In this talk I will describe a fourth fundamental concept, proposed only recently, namely the "Principle of Diminishing Potentialities". I will then show how it enables one to come up with a precise notion of "events" in Quantum Mechanics and with a new understanding of the time evolution of states of isolated systems.
 As results, the "measurement problem" and the unitarity- or information paradox disappear, and a "Quantum Mechanics without Observers" emerges. 

 

English

 

The next CPHT colloquium will take place on Thursday, February 6 at 2 pm in the Louis Michel conference room.

The speaker will be Zaki Leghtas, and his topic will be quantum information.

"Quantum computing with Schrödinger cat states".

Superconducting qubits are one of the most promising platforms to implement quantum technologies. Quantum processors of tens of qubits are now available, and exciting applications with these intermediate size systems are in perspective. However, many algorithms, including all those with a proved quantum speed-up, require extremely low error rates. This will most likely require quantum error correction (QEC). Unfortunately, current QEC architectures require daunting overheads in physical qubits and control electronics. The goal of this research is to reduce this overhead, and our approach is based on two key ideas. First, we redundantly encode quantum information in Schrödinger cat states embedded in superconducting resonators. Second, we engineer non-linear dissipation to protect and manipulate this information.
 
English

 

Le processus de définition de la stratégie européenne en physique des particules est en son cours. Après la réunion de Grenade, le « Physics Briefing Book » a été publié en septembre, et depuis le groupe restreint sur la stratégie prépare la session de rédaction de Bad Honnef (20-24 janvier 2020) qui doit déboucher sur des recommandations qui seront données au Conseil du CERN.

Plusieurs scénarios de futurs collisionneurs sont discutés dans ce cadre-là. Nous vous proposons d'échanger ensemble à ce sujet, le lundi 13 janvier de 14h à 17h dans l'amphi Charpak du LPNHE. Il s'agira notamment de présenter les scénarios considérés et de discuter d'une position commune française à défendre à Bad Honnef.

Inscription (gratuite mais indispensable) sur https://indico.in2p3.fr/event/20221/

Divers documents d’information sont disponibles aux liens suivants:

http://arxiv.org/abs/1912.11871

https://arxiv.org/abs/1912.13466

http://cds.cern.ch/record/2705370

 

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