PhD student (M/F) in theoretical physics – disorder and relaxation in loop models

Job Description

Thesis Subject

Disorder and relaxation in topologically constrained loop models: from stochastic dynamics to Rokhsar-Kivelson quantum spectra

This PhD project investigates the effect of quenched disorder on the relaxation dynamics of loop systems subject to topological constraints. The reference model is related to the domain-wall representation of the Ising model on the triangular lattice and to the graph expansion of the Ising model on the honeycomb lattice.

The main objective is to understand how spatial disorder, even when weak, can modify relaxation times when local dynamics forbids loop reconnection. Particular attention will be paid to distinguishing between a perturbative regime, long crossover behavior, and a possible asymptotic regime dominated by disorder or rare events.

The project will combine analytical and numerical methods, including exact methods for the Ising model and the Kac-Ward formalism, reversible Markov chains, renormalization-group techniques, spectral analysis, large-deviation methods, and kinetic Monte Carlo simulations. Detailed balance will also make it possible to map the stochastic generator onto a Rokhsar-Kivelson Hamiltonian, thereby establishing a direct connection between classical relaxation dynamics and quantum spectra.

Your Work Environment

The PhD will be carried out primarily at the Laboratoire de Physique des Solides, UMR 8502, CNRS – Université Paris-Saclay, in Orsay, within a research environment in condensed matter physics and statistical physics.

The PhD student will work under the scientific supervision of Chunxiao Liu. They will benefit from scientific interactions within the laboratory, particularly in the areas of strongly correlated quantum systems, frustrated magnetism, topological phenomena, and statistical physics.

The project has a strong analytical and numerical component and will involve the development of computational methods, simulations, and spectral-analysis tools. During the PhD, the student will progressively develop expertise in Ising and loop models, Markov processes, disordered systems, renormalization methods, rare-event phenomena, and Rokhsar-Kivelson Hamiltonians.

The student will also participate in the scientific activities of the laboratory, including seminars, collaborations, and, where appropriate, conferences and thematic schools.

Constraints and risks

The project is theoretical and computational in nature and does not involve any particular experimental risks. The work will be carried out primarily on a computer. Occasional travel within France or abroad may take place in connection with scientific collaborations, conferences, workshops, or thematic schools.

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

The research professions