Supersolidity in Optically Trapped Polariton Condensates

TL;DR

This paper proposes exciton-polariton superfluids in optically trapped annular geometries as a new platform for realizing supersolidity, supported by theoretical analysis and experimental evidence of spontaneous spatial order and characteristic excitations.

Contribution

It introduces a novel experimental platform for supersolidity using exciton-polariton superfluids in optically induced traps, with theoretical and experimental validation.

Findings

Observation of spontaneous spatial order in polariton superfluids

Agreement between experimental results and mean-field theory

Detection of zero-energy Nambu-Goldstone modes

Abstract

Superfluids under specific conditions can exhibit spontaneous breaking of continuous translation symmetries and form exotic spatially ordered states of matter known as supersolids. Despite its early theoretical prediction, it took over half-a-centrury to experimentally demonstrate the supersolid phase in ultracold atomic Bose-Einstein condensates, forming due to long-range interatomic interactions. Here we propose as a promising new platform for supersolidity exciton-polariton superfluids, confined in annular optically induced traps. The supersolid phase emerges due to effective attractive interactions, mediated by the normal excitonic component of the system. Experimental demonstration of spontaneously formed spatially ordered phase is in agreement with detailed mean-field theoretical analysis and numerical simulation. The spontaneous character of the observed supersolid transition is further evidenced by the formation of specific zero-energy Nambu-Goldstone modes in the collective excitation spectrum.