Description du sujet de thèse

Embedding quantum materials in photonic cavities offers a novel way of modifying properties of these materials. This novel field of research has been motivated by the progress coming from the experimental advances in reaching the ultrastrong light-matter coupling regime that allows one to predict and study new physical phenomena. Breakdown of topological protection in the quantum Hall effect is the most striking experimental demonstration of cavity control of quantum materials. Topological materials such as topological insulators and topological superconductors attracted a lot of attention in the past decades due to their potential application in the field of quantum technologies. The prototype model for a topological superconductor is the Kitaev chain model describing a one-dimensional topological superconductor with zero-energy Majorana bound states emerging at its ends. Coupling topological materials to cavity photons offers a new way to probe and to control their topological properties. In particular, it was demonstrated that the presence of the Majorana bound states in the Kitaev chain embedded in a cavity could be probed via cavity spectral function. Moreover, the topological phase transition point in the prototype model for topological insulators - Su-Schrieffer-Heeger model - is modified by photon coupling.

The goal of the PhD project is to study the topological materials coupled to cavity photons, with the aim of using cavity embedding to probe, to control, and to design new topological phases. The project will focus on electronic tight-binding models in the presence of the coupling to photons and electron-electron interactions. One objective of the project is to propose a new approach for observing topological bound states based on cavity spectroscopy. Another objective is to consider the topological material coupled to a single mode cavity in the resonant regime and to study the properties of hybrid light-matter states - polaritons - emerging in this regime. The most ambitious objective is to design topological states in electronic materials with trivial band topology with quantum light.

Contexte de travail

The Centre de Physique Théorique (CPHT) is a joint research unit (UMR 7644) of CNRS and Ecole Polytechnique. The CPHT gathers research scientists working in diverse domains of fundamental and applied Physic. The PhD student will join the Condensed Matter group at CPHT. The PhD student will be registered with the Doctoral School of the Institut Polytechnique de Paris.

Contraintes et risques

no risks

Informations complémentaires

M2 internship relevant to the project; excellent oral and written communication skills in English