Unconventional Berezinskii-Kosterlitz-Thouless Transition in the Multicomponent Polariton System

Abstract

We study a four-component polariton system in the optical parametric oscillator regime consisting of exciton/photon and signal/idler modes across the Berezinskii-Kosterlitz-Thouless (BKT) transition. We show that all four components share the same BKT critical point, and algebraic decay of spatial coherence with the same critical exponent. However, while the collective excitations in different components are strongly locked, both close to and far from criticality, the spontaneous creation of topological defects in the vicinity of the phase transition is found to be largely independent of the inter-component mode locking, and instead strongly dependent on the density within a given mode. This peculiar characteristic allows us to reveal a novel state of matter, characterised by configurations of topological defects proliferating on top of a superfluid with algebraic decay of coherence, observation of which is demonstrated to be within reach of current experiments.

Noise-induced transition from superfluid to vortex state in two-dimensional nonequilibrium polariton condensates: Semianalytical treatment

“…( 26) together with Eqs. ( 17), ( 20), (21), and ( 23)- (25), can be considered as a function of three independent parameters: γ/g, κ and ǫ + /ǫ − . In Fig.…”

“…In two dimensions, the KPZ phase dynamics was predicted to make long range phase coherence impossible in isotropic systems [13,17]. Numerical studies on the other hand have shown a transition toward a state with algebraic decay of the coherence [18] and an associated disappearance of vortex-antivortex pairs [18][19][20][21] without the formation of topological defects even when the spatiotemporal correlations feature KPZ scaling [22,23]. Since computational resources limit the system sizes for numerical studies, the discrepancy between the renormalisation group studies could be due to finite size effects, but at present it does not seem that the issue is fully settled.…”