Collective Excitations, Nambu-Goldstone Modes and Instability of Inhomogeneous Polariton Condensates

TL;DR

This paper theoretically investigates non-equilibrium microcavity-polariton condensates in a harmonic trap, analyzing their steady states, collective excitations, and instabilities, including Nambu-Goldstone modes and supercurrent-driven bifurcations.

Contribution

It provides a theoretical analysis of collective excitation modes and instabilities in inhomogeneous polariton condensates, highlighting the role of Nambu-Goldstone modes and bifurcation phenomena.

Findings

Existence of Nambu-Goldstone modes indicating spontaneous symmetry breaking

Identification of bifurcation points related to pumping power and spot size

Characterization of instability mechanisms involving inward supercurrent flow

Abstract

We study non-equilibrium microcavity-polariton condensates (MPCs) in a harmonic potential trap theoretically. We calculate and analyze the steady state, collective-excitation modes and instability of MPCs. Within excitation modes, there exist Nambu-Goldstone modes that can reveal the pattern of the spontaneous symmetry breaking of MPCs. Bifurcation of the stable and unstable modes is identified in terms of the pumping power and spot size. The unstable mechanism associated with the inward supercurrent flow is characterized by the existence of a supersonic region within the condensate.