Pancharatnam-Berry phase in condensate of indirect excitons

TL;DR

This paper demonstrates the observation of the Pancharatnam-Berry phase in a condensate of indirect excitons, linking phase shifts in interference patterns to spin precession and coherence in a GaAs quantum well system.

Contribution

It provides the first experimental evidence of the Pancharatnam-Berry phase in indirect exciton condensates and elucidates its relation to polarization and coherence properties.

Findings

Observation of phase shifts in interference fringes due to the Berry phase

Correlation between phase shifts, polarization patterns, and coherence onset

Identification of the Berry phase as arising from coherent spin precession

Abstract

We report on the observation of the Pancharatnam-Berry phase in a condensate of indirect excitons (IXs) in a GaAs coupled quantum well structure. The Pancharatnam-Berry phase leads to phase shifts of interference fringes in IX interference patterns. Correlations are found between the phase shifts, polarization pattern of IX emission, and onset of IX spontaneous coherence. The Pancharatnam-Berry phase is acquired due to coherent spin precession in IX condensate. The effect of the Pancharatnam-Berry phase on the IX phase pattern is described in terms of an associated momentum.