Polariton dynamics in strongly interacting quantum many-body systems

TL;DR

This paper develops a theoretical framework for light propagation in strongly interacting atomic Bose-Einstein condensates, revealing how many-body correlations significantly alter optical properties and quasiparticle behavior.

Contribution

It introduces a new theory describing polaron-polaritons in strongly interacting quantum systems, highlighting their spectral features and damping behavior.

Findings

Existence of well-defined polaron-polaritons in the system

Nonmonotonic damping dependence on light-matter coupling

Crossover between polariton and polaron-polariton quasiparticles

Abstract

We develop a theory for light propagating in an atomic Bose-Einstein condensate in the presence of strong interactions. The resulting many-body correlations are shown to have profound effects on the optical properties of this interacting medium. For weak atom-light coupling, there is a well-defined quasiparticle, the polaron-polariton, supporting light propagation with spectral features differing significantly from the noninteracting case. The damping of the polaron-polariton depends nonmonotonically on the light-matter coupling strength, initially increasing and then decreasing. This gives rise to an interesting crossover between two quasiparticles: a bare polariton and a polaron-polariton, separated by a complex and lossy mixture of light and matter.