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 a joint research unit of CNRS and Ecole Polytechnique, and has a partnership with the Collège de France. His director is Jean-René Chazottes, Senior Researcher at CNRS.
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

 

 

Second announcement: registration for "Quantum gravity, random geometry and holography" From January 9th to February 17th, 2023, at the Institut Henri Poincaré (Paris)

Important: the deadline for financial support requests is June 15th, 2022

Program : The thematic six-weeks program will include two workshops (weeks 2 and 5), introductory lectures (weeks 1 and 4), two general public lectures (to be announced), and more (informal gatherings and seminars).

Organizing committee : John Barrett (University of Nottingham), Dario Benedetti (CNRS, École Polytechnique), Joseph Ben Geloun (Université Sorbonne Paris Nord), Renate Loll (Radboud University Nijmegen)

More information : here

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The 3rd CPHT Young Researchers Seminar will be held on March 31, 2022 at 3:00 p.m. in the Louis Michel Conference Room with two presentations given by :

Filippo Sottovia : Hydrodynamic description of Landau instabilities in superfluids

Jan Schneider : Entanglement spectrum and quantum phase diagram of the long-range XXZ chain via tensor network techniques

The seminar will be followed by a high tea.

English

Séminaires des Cordes
le mercredi 23 mars 2022
Salle de conférence Louis Michel, CPHT, Ecole Polytechnique

11h - 11h45
Luca Ciambelli
Universal symmetries of gravity

Abstract: I will derive the universal group of symmetries stemming from diffeomorphisms on a codimension-2 surface S at finite distance. I will then compute Noether charges in Einstein gravity and prove that, treating the embedding fields carefully, their algebra is a faithful representation of the aforementioned group of symmetries. This is then shown to be canonically realized on a suitably enlarged covariant field space, where one treats the embedding fields as part of the field space. This solves an old question in gravity, which is to find a field space where all gravitational charges are canonical, i.e. integrable, and thus represented through Poisson brackets.

12h - 12h45
Romain Ruzziconi
A Carrollian Perspective on Celestial Holography

Abstract: I will present a holographic description of gravity in 4d asymptotically flat spacetime in terms of a 3d sourced conformal Carrollian field theory. The external sources encode the leaks of gravitational radiation at null infinity. The Ward identities of this theory are shown to reproduce those of the 2d celestial CFT after relating Carrollian to celestial operators. This suggests a new set of interplays between gravity in asymptotically flat spacetime, sourced conformal Carrollian field theory and celestial CFT. 

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Aspects of gravity, mathematics and physics
21-22 mars 2022 Palaiseau (France)

Amphithéâtre Becquerel, École Polytechnique

Cette conférence est organisée par le Centre de Mathématiques Laurent Schwartz et le Centre de Physique Théorique de Polytechnique.

Orateurs

Nicolas Besset (Paris Saclay) Guillaume Bossard (Polytechnique)
Eleonora Di Nezza (Polytechnique)
Grigorios Fournodavlos (Université de Crète et Université de Princeton)
Jose Luis Jaramillo (Université de Bourgogne Franche-Comté)
Leonhard Kehrberger (Université de Cambridge)
Blagoje Oblak (Polytechnique et Sorbonne Université)
Harvey Reall (Université de Cambridge)
Danièle Steer (Université de Paris)
Martin Taylor (Imperial College)
Michal Wrochna (Université de Cergy)
Zoe Wyatt (King's College London)

Organisateurs

Dietrich Häfner (UGA), Cécile Huneau (Polytechnique), Karim Noui (Paris Saclay), Marios Petropoulos (Polytechnique)

Inscription obligatoire ici

Lien vers l'affiche ici

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Marcello Turtulici soutiendra publiquement ses travaux de thèse le 10 décembre 2021  au CPHT, Salle de conférence Louis Michel.

Titre de la thèse : "Ab-initio investigation of non-stoichiometric transition metal oxides"

Composition du Jury

Rapporteurs : Ferdi Aryasetiawan, Jan Martin Tomczak
Presidente : Lucia Reining
Examinateurs : Dipankar Das Sarma, Alaska Subedi
Directrice de these : Silke Biermann

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Phd student

Research group : Mathematical physics

Thesis: "Renormalization of quantum field theories that break translation invariance."
Advisor: Christoph Kopper

Research interests

flow equations, renormalization group, quantum field theory, half-space, lattice, film geometry, Casimir effect

Quantum field theories that break translation invariance appear in many physical context. The translation invariance can be broken by the regularization scheme used such as the lattice regularization [1], by the geometry of the space-time (a Riemanian manifold for example) [2], or by the presence of a boundary. When the loss of this symmetry is induced by the properties of the space-time, the renormalization of the QFT is affected. The less symmetric the theory is, the more counter-terms are needed to make it finite. The aim of this thesis is to study first the perturbative renormalization of the massive scalar field theory with a quartic interaction regularized by a lattice, using the method of the flow equations and prove that the Euclidean symmetries are restored in the continuum limit. We would like also to investigate the perturbative renormalizability of boundary field theories. The massive scalar field theory in a half-space [3] is the simplest model of such theories. We compute first all the possible propagators that correspond to all possible boundary conditions and prove the renormalizability of this theory for the Robin boundary condition.

[1] M. Borji, Ch. Kopper, Perturbative renormalization of the lattice regularized phi 44 with flow equations, Journal of Mathematical Physics. 2020;31(11):112304.
[2] Ch. Kopper, V. F. Müller, Renormalization proof for massive phi44 theory on Riemannian manifolds, Communications in Mathemathical Physics 2007; 275(2): 331-372.
[3] H.W. Diehl, in: Phase Transitions and Critical Phenomena, Vol. 10. Eds. C. Domb and J.L. Lebowitz (Academic Press, London, 1986) p. 75

 

Address CPHT, Ecole Polytechnique, 91128 Palaiseau cedex, France
Phone number 33 (0)1 69 33 42 40
Contact firstname.lastname@polytechnique.edu
Office Building 0, office 00.1019

 

English

 

The 2nd CPHT Young Researchers Seminar will be held on December 9, 2021 at 3:00 p.m. in the Louis Michel Conference Room with three presentations:

Yorgo Pano : Celestial holography in a nutshell

Duifje van Egmond : A novel background field approach to the confinement-deconfinement transition

Benjamin Bacq-Labreuil : Into the physics of real copper oxide materials

The seminar will be followed by a high tea.

English

 

Xiang ZHAO soutiendra publiquement ses travaux de thèse le jeudi 25 novembre 2021 à 10h00 au CPHT, Salle de conférence Louis Michel.

Titre de la thèse : "Aspects of Conformal Field Theories and Quantum Fields in AdS"
Directeur de thèse : Balt Van Rees

Participer à la réunion Zoom pour la soutenance de thèse :
https://us06web.zoom.us/j/87068486326?pwd=a0JMRkZBdEpkYzVDR0h4N2piQ1hNUT09
Meeting ID: 870 6848 6326
Passcode: 245657

Composition du Jury

(1) Christopher BEEM, Associate Professor, Oxford University (Rapporteur)
(2) Nikolay BOBEV, Associate Professor, KU Leuven (Rapporteur)
(3)Costas BACHAS, Directeur de Recherche, ENS (Examinateur)
(4) Christoph KOPPER, Professeur, Ecole Polytechnique (CPHT) (Examinateur)
(5) Eric PERLMUTTER, Assistant Professor, Saclay (IPHT) (Examinateur)
(6) Balt VAN REES, Professeur, Ecole Polytechnique (CPHT) (Directeur de thèse)

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