Journée Théorie du CPTGA 2025

mercredi 8 oct. 2025, 07:30 → 17:05 Europe/Paris

Auditorium (LAPTh)

Le CPTGA vous invite à sa 16ème "Journée de Physique Théorique".

Le but de ces journées est de permettre des échanges entre physicien.ne.s théoricien.ne.s de Grenoble/Annecy travaillant dans des domaines très variés. Il est à la fois question de comprendre de la belle science et de découvrir le travail des collègues locaux.

Le thème de la Journée Théorie 2025 est "Physique (et) Statistique"

Le programme sur le site web est provisoire. Il sera complété au fur et à mesure.

Merci de s'inscrire avant le 23 septembre 2025.

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The CPTGA invites you to its 16th "Theoretical Physics Day."

The aim of these days is to foster exchanges between theoretical physicists from Grenoble/Annecy working in a wide range of fields. It is both an opportunity to explore beautiful science and to discover the work of local colleagues.

The theme of the 2025 Theoretical Physics Day is "Physics (and) Statistics."

The program on the website is provisional and will be updated progressively.

Please register before September 23, 2025.

Bus departure from Grenoble: 7:30 Polygone 8:00 Campus

Estimated time of arrival in Annecy (LAPTh): 9:45

Welcome in Annecy

Gilles Parez (LAPTh): Entanglement in solvable quantum many-body systems

Quantum entanglement is a striking feature of the quantum world, with no classical counterpart. Over the last two decades, it has become a meeting ground between quantum information and other areas of physics, including statistical mechanics, condensed matter, and high-energy theory. In many-body systems, entanglement is closely tied to emergent phenomena such as quantum phase transitions, topological phases, and the emergence of thermodynamics far from equilibrium. Exact results obtained in solvable models and field theories play a central role in this program, offering sharp insights that guide our understanding of more complex systems. In this talk, I will give a broad overview of this active field of research and highlight several illustrative results.

CPTGA_8oct_2025_Parez.pdf

Pause café (Coffea break)

Jeanne Colbois (Institut Néel): Tensor networks for classical frustrated spin systems

TNsFrustration_Colbois.pdf

Yoann Genolini (LAPTh): Statistics of cosmic-ray displacement in turbulent magnetic fields

talk_Genolini_Yoann_CPTGA.pdf

Lunch break: Vegetarian meal

Loic Herviou (LPMMC): Tensor network simulations of 2+1D CFT: the Fuzzy sphere

The study of conformal field theories (CFTs) in 2+1 dimensions represents a significant challenge in theoretical physics due to their strong coupling nature and the lack of exact solutions.
In this talk, I will present recent advancements in numerical simulations of these CFTs using tensor network methods combined with the fuzzy sphere regularization technique.
This approach provides a powerful framework for non-perturbative studies of 2+1D CFTs, enabling (a somewhat) precise extraction of conformal data.

The fuzzy sphere regularization involves constructing quantum systems on a spherical geometry with a non-commutative structure, which serves as an ultraviolet regulator while maintaining the full SO(3) rotational symmetry of the sphere.
This construction is based on the well-known Integer quantum Hall physics and the physics of quantum Hall ferromagnets. After a brief introduction of tensor networks, I will discuss the strength and limitations of this method through the examples of the Ising and O(N) CFTs.
I will also discus its generalization to non-unitary CFTs, such as the Yang-Lee CFT or to boundary CFTs (BCFTs) using a fuzzy hemisphere.

PresCPTGA_Herviou.pdf

Nina Javerzat (Institut Fourier): Rényi complexities in disordered systems

Pause (break)

Alexander Erlich (LIPhy): Incompatibility-driven growth

Bus departure from Annecy: 17:00

Estimated time of arrival in Grenoble : 19:00 at polygone