Le Centre de Physique Théorique (CPHT) réunit des chercheurs dont les activités couvrent un large spectre de la Physique, tant dans ses aspects fondamentaux qu'appliqués.
Le CPHT est une unité mixte de recherche (UMR 7644) du Centre National de la Recherche Scientifique (CNRS) et de l’Ecole polytechnique. Au niveau du CNRS, il est rattaché à l’Institut de physique. Le CPHT a également un partenariat avec le Collège de France.
Le CPHT, dirigé par Jean-René Chazottes, directeur de Recherche au CNRS, est implanté sur le campus de l’Ecole Polytechnique à Palaiseau, dans le bâtiment 6 et dans l'aile 0 du bâtiment 5. Le secrétariat se situe dans le Bâtiment 6, bureaux 06.1046 et 06.1045. 
 

Adresse postale : 
CPHT 
Ecole Polytechnique 
91128 Palaiseau cedex 
France

Tél. Secrétariat : 01 69 33 42 01

Pour écrire un email à un membre du laboratoire : prenom.nom@polytechnique.edu

 

Séminaire conjoint LSI+CPHT+PMC = M4S

Mardi 22 avril à 11h00

Salle de conférence Louis Michel (CPHT)

Programming twist angle and strain gradients in two-dimensional materials by bending

Maëlle Kapfer
(Post-doc C2N)

The possibility to isolate atom-thick layer of material from a bulk crystal allows the design of structures with a wide range of properties [1]. In particular, by twisting those single layer sheets, a periodic potential, called moiré potential, is superimposed over the lattice modifying the properties of the parent material [2], [3]. Twisted two-dimensional materials have generated tremendous excitement as a platform for achieving quantum properties on demand. However, the moiré pattern is highly sensitive to the interlayer atomic registry, and current assembly techniques suffer from imprecise control of the average twist angle, spatial inhomogeneity in the local twist angle, and distortions due to random strain [4]. Here, we demonstrate a new way to manipulate the moiré patterns in hetero- and homo-bilayers through in-plane bending of monolayer ribbons, using the tip of an atomic force microscope [5]. This technique achieves continuous variation of twist angles with improved twist-angle homogeneity and reduced random strain, resulting in moiré patterns with highly tunable wavelength and ultra-low disorder. Our results pave the way for detailed studies of ultra-low disorder moiré systems and the realization of precise strain-engineered devices.

[1] K. S. Novoselov et al., Science, 353, aac9439 (2016)
[2] Y. Cao et al., Nature, 556, 43–50 (2018)
[3] M. Yankowitz et al., Science, 363, 1059–1064, (2019)
[4] C. N. Lau et al., Nature, 602, 41–50, (2022)
[5] M. Kapfer et al., Science, 381,. 677–681, (2023)

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Le séminaire Seed de mathématiques et de physique est une série de séminaires qui vise à favoriser les interactions entre les mathématiciens et les physiciens théoriques, en particulier parmi les jeunes chercheurs. Il est structuré en périodes thématiques de trois mois.

Nous organisons un atelier en personne à l'Institut Pascal (Orsay) reprenant les trimestres de cette année académique avec des contributions de Nicolas Curien, Boris Pioline, Clément Delcamp, Balt van Rees et Stavros Garoufalidis

Inscription gratuite mais obligatoire.

Organisateurs : Matteo D’Achille, Aymane El Fardi, Veronica Fantini, Emmanuel Kammerer, Edoardo, Sophie Mutzel, Junchen Rong

Plus d'information : https://indico.ijclab.in2p3.fr/event/11715/overview

Poster

Français

 

We are pleased to announce that the next "Biséminaire Friedmann CPHT-LLR" will be held on May 6, 2025 at the CPHT (Ecole Polytechnique), Salle Louis Michel.

11:00 - Sébastien RENAUX-PETEL (Institut d'Astrophysique de Paris)

New Particles in the Sky
Inflation literally acts as a cosmological collider: it spontaneously produces all types of particles, which leaves peculiar imprints in the correlation functions of primordial density fluctuations. Primordial correlators thus hold the key to high-energy physics inaccessible by other means. However, they are much harder to compute than flat space amplitudes. In this talk, I will describe these opportunities and challenges, as well as analytical and numerical techniques that have been developed in the past few years to better understand quantum field theory in curved spacetime.

14:30 - Vincent VENIN (Laboratoire de Physique, ENS Paris)

Quantum diffusion and primordial black holes in the early universe
When primordial inhomogeneities are produced with sufficiently large amplitude in the early universe, they may subsequently collapse into primordial black holes. I will explain why the effect of quantum diffusion during inflation needs to be taken into account in such a case, and how the statistics of cosmological fluctuations can be predicted within the formalism of stochastic inflation. Quantum diffusion leads to a peculiar type of non-Gaussianity that cannot be captured by perturbative parametrisations. This leaves specific imprints on the statistics of collapsed structures that I will discuss. In particular, I will present recent results on the clustering of primordial black holes, which conditions the rate at which they merge and emit gravitational waves.

Lien zoom : https://ecolepolytechnique.zoom.us/j/7410042935

Comité Friedmann: S. Biermann, J.-R. Chazottes, M. de Naurois, P. M. Petropoulos, Y. Sirois

Organised in cooperation with the Fondation de l'X, the Fonds Alexandre Friedmann and the Laboratoire Leprince-Ringuet (Ecole polytechnique).

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Cours Thématiques du CPHT

Title: An Introduction to Conformal Field Theory in 2 + 1 Dimensions

Two lectures by Junchen RONG (CPHT)

Centre de Physique Théorique, École polytechnique
Salle de conférences Louis Michel
April 7 & 11, 2025 from 11:00 to 13:00

Abstract:
In this series of lectures, I will explore conformal field theories (CFTs) in 2 + 1 dimensions and the renormalisation group flows connecting them. I will begin by examining scalar CFTs, which correspond to Wilson-Fisher fixed points in 4− ε dimensions, focusing on their stability properties from a modern perspective. Following this, I will discuss 2 + 1 dimensional gauge theories with bosonic or fermionic matter. If time permits, I will also discuss the connections between these CFTs and quantum/statistical phase transitions.

Lien zoom : https://ecolepolytechnique.zoom.us/j/7410042935

Organisers: Adrien FIORUCCI, Marios PETROPOULOS, Mikel SANCHEZ

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Le cycle de cours et séminaires de la chaire Physique de la Matière Condensée du Collège de France débutera le mercredi 30 avril et a pour sujet cette année : "Fermions froids et simulation quantique"

Les cours sont en français et les séminaires en anglais.
Les cours peuvent être validés au titre de la formation doctorale: inscriptions en suivant ce lien.

Organisation : Antoine Georges (Professeur, Collège de France)

Plus d'informations : ici

Affiche

Français

Out-of-equilibrium, Tilings & the Conformal Bootstrap

Centre de Physique Théorique, salle Louis Michel
Ecole polytechnique

— March 31, 2025 —

Accueil des participants/Café à partir de 10h00

SPEAKERS

10:30 – 11:30 Kirone Mallick (IPhT, CEA Saclay) An exact solution of the macroscopic fluctuation theory

11:30 – 11:45 Coffee break

11:45 – 12:45 Ada Altieri (MSC, Université Paris Cité) Disordered ecologicald dynamics and Moment-matching Inference for gut microbial communities

12:45 – 14:15 Lunch time at the Magnan

14:15 – 15:15 Balt Van Rees  (CPHT, Ecole polytechnique) Bootstrapping frustrated magnets

15:15 – 16:15 Grégory Schehr (LPTHE, Sorbonne Université) Universal distribution of the number of minima for random walks and Lévy flights

16:15 – 16:30 Coffee break

16:30 – 17:30 Jean-René Chazottes (CPHT, Ecole polytechnique) Thermodynamic Formalism, Symbolic Dynamics, and Quasicrystal Models

ORGANISERS
Adrien Fiorucci, Marios Petropoulos, Mikel Sanchez

Lien zoom

Programme détaillé

Poster

Indéfini

The CPHT Thesis Day will take place on Thursday January 23, 2025 in the Becquerel amphitheatre.

Programme of the PhD day
FY = First year

9am —> 10.30am: First session

 
Maxence Baccara (FY)
Tom de Coninck (FY)
Adrien Gallin (FY)
Hoyeon Won
Mathieu Beauvillain
Fanny Eustachon
Sariah AlSaati
Godefroy Meynard
 
10.30am —> 11 am: Coffee break
 
11am —> 12:15am: Second session
 
Maddalena Ferragatta (FY)
Antoine Misery (FY)
Clément Supiot
Victor Tomas Mari Surkau
Tristan Gamot
Adrien Kahn
 
12:15am —> 2pm: Buffet in room Jean Lascoux
 
2pm —> 3.15pm: Third session
 
Magali Korolev (FY)
Danilo Nascimento Guimaraes (FY)
Runbin Luo (FY)
Louis Sharma (FY)
Thomas Pochart
Victor Franken
Liam Rampon
Ahmedeo Shokry
 
3.15pm —> 3.45pm: Coffee break
 
3.45pm —> 5pm: Fourth session
 
Amine Announ (FY)
Arthur Klause (FY)
Owen Colire (FY)
Xiaoxu Zhou (FY)
Victor Dubois
Pierre Wang
Shengjie Yu
Felix Fossati
 
5.pm: End of the day
Français

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