Bloch Oscillations of an Exciton-polariton Bose-Einstein Condensate

TL;DR

This paper theoretically investigates Bloch oscillations in exciton-polariton Bose-Einstein condensates, demonstrating conditions under which oscillations can be observed despite short particle lifetimes and structural disorder.

Contribution

It introduces a novel structure for observing Bloch oscillations in exciton-polaritons, accounting for disorder and non-linear interactions to enable oscillation recovery.

Findings

Regular oscillations in a perfect lattice in the linear regime

Disorder localizes particles but can be screened by interactions in the non-linear regime

High chemical potential causes Landau-Zener tunneling and delocalization

Abstract

We study theoretically Bloch oscillations of half-matter, half-light quasi-particles: exciton-polaritons. We propose an original structure for the observation of this phenomenon despite the constraints imposed by the relatively short lifetime of the particles and the limitations on the engineered periodic potential. First, we focus on the linear regime in a perfect lattice where regular oscillations are obtained. Second, we take into account a realistic structural disorder known to localize non-interacting particles, which is quite dramatic for propagation-related phenomena. In the non-linear condensed regime the renormalization of the energy provided by interactions between particles allows us to screen efficiently the disorder and to recover oscillations. This effect is useful only in a precise range of parameters outside of which the system becomes dynamically unstable. For a large chemical potential of the order of the potential's amplitude, a strong Landau-Zener tunneling tends to completely delocalize particles.