Léonie Canet (Université Grenoble Alpes)

Kardar-Parisi-Zhang universality in  exciton-polariton condensates

Since the seminal paper by Kardar, Parisi and Zhang (KPZ) in 1986 on kinetic roughening of classical growing interfaces, the KPZ equation has arisen as a fundamental model in statistical physics for non-equilibrium scaling phenomena and phase transitions. Unexpectedly, it still unfolds new branching, such as a connection with the phase dynamics of open quantum systems displaying macroscopic spontaneous coherence.

In this talk, I will first give an overview of the realm of the KPZ equation. I will then focus on exciton-polaritons. These are hybrid quasi-particles emerging in semiconductor optical cavities from the strong coupling between electronic excitations in a quantum well and cavity photons. They behave collectively as a quantum fluid, featuring a Bose-Einstein condensation, which is genuinely out-of-equilibrium  because of its driven-dissipative nature. I will explore the connection between the exciton-polariton condensate and the KPZ universality, and show that it extends well beyond the mere KPZ critical exponents. I will present results from both numerical simulations and a recent experiment.

Q. Fontaine et al, Nature 608, 687 (2022)
K. Deligiannis, D. Squizzato, A. Minguzzi, LC, EPL 132, 67004 (2021)
D. Squizzato, LC, A. Minguzzi, PRB 97, 195453 (2018)