Supersolidity of polariton condensates in photonic crystal waveguides

TL;DR

This paper theoretically predicts a supersolid phase in polariton condensates within photonic crystal waveguides, characterized by a second emission threshold and spontaneous symmetry breaking, with proposed experimental signatures for detection.

Contribution

It introduces a novel mechanism for supersolidity in driven-dissipative polariton systems and identifies clear experimental signatures for its observation.

Findings

Prediction of a second emission threshold due to nonlinear scattering

Identification of spontaneous breaking of phase and translational symmetries

Proposal of experimental signatures for supersolidity detection

Abstract

Condensation of exciton-polaritons has been recently observed in one-dimensional photonic crystal waveguides, exploiting the interplay of long-lived gap confined eigenmodes and negative mass polariton branches. Here we focus on the theoretical emergence of a second emission threshold, in addition to the one associated with condensation at zero-momentum, due to the nonlinear polariton scattering from the condensate into finite momentum eigenmodes. The physics of this spatially modulated condensate is related to a spontaneous breaking of both phase and translational symmetries simultaneously, bearing strong similarities with the highly sought supersolid phase in Helium and ultracold atomic gases but with a novel mechanism typical of the driven-dissipative scenario. We then propose clear-cut and unequivocal experimental signatures that would allow to identify supersolidity phenomena in polariton condensates