Cavity quantum electrodynamics with many-body states of a two-dimensional electron gas

TLDR

Light‑matter interaction underpins the engineering of novel states of matter, and reversible exciton–photon coupling has enabled condensation and superfluidity of nonequilibrium quasiparticles with a photonic component. The study investigates cavity‑polaritons in a high‑mobility two‑dimensional electron gas exhibiting strongly correlated phases. The authors examined cavity‑polaritons formed with a high‑mobility two‑dimensional electron gas that displays strongly correlated phases. On resonance with the Fermi level, the cavity revealed novel many‑body physics from a dynamical hole‑scattering potential, while in magnetic fields polaritons exhibited signatures of integer and fractional quantum Hall states, establishing a platform to probe nonequilibrium quantum Hall dynamics and achieve ultrastrong optical nonlinearities via density‑dependent polariton splitting.

Abstract

Light-matter interaction has played a central role in understanding as well as engineering new states of matter. Reversible coupling of excitons and photons enabled groundbreaking results in condensation and superfluidity of nonequilibrium quasiparticles with a photonic component. We investigated such cavity-polaritons in the presence of a high-mobility two-dimensional electron gas, exhibiting strongly correlated phases. When the cavity was on resonance with the Fermi level, we observed previously unknown many-body physics associated with a dynamical hole-scattering potential. In finite magnetic fields, polaritons show distinct signatures of integer and fractional quantum Hall ground states. Our results lay the groundwork for probing nonequilibrium dynamics of quantum Hall states and exploiting the electron density dependence of polariton splitting so as to obtain ultrastrong optical nonlinearities.