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

We study a four-component polariton system in the optical parametric oscillator regime consisting of exciton, photon, signal, and 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 intercomponent 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, characterized 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

Full and fractional defects across the Berezinskii-Kosterlitz-Thouless transition in a driven-dissipative spinor quantum fluid

We investigate the properties of a two-dimensional \emph{spinor} microcavity polariton system driven by a linearly polarised continuous pump. In particular, we establish the role of the elementary excitations, namely the so-called half-vortices and full-vortices; these objects carry a quantum rotation only in one of the two, or both, spin components respectively. Our numerical analysis of the steady-state shows that it is only the half-vortices that are present in the vortex-antivortex pairing/dissociation responsible for the Berezinskii-Kosterlitz-Thouless transition. These are the relevant elementary excitations close to the critical point. However, by exploring the phase-ordering dynamics following a sudden quench across the transition we prove that full-vortices become the relevant excitations away from the critical point in a deep quasi-ordered state at late times. The time-scales for half-vortices binding into full vortices are much faster than the vortex-antivortex annihilations.Comment: 6 pages, 3 figure

Non-equilibrium berezinskii-kosterlitz-thouless transition in driven-dissipative condensate

We study the two-dimensional phase transition of a driven-dissipative system of exciton-polaritons under non-resonant pumping. Stochastic calculations are used to investigate the Berezinskii-Kosterlitz-Thouless–like phase diagram for experimentally realistic parameters, with a special attention to the non-equilibrium features

Non-equilibrium Berezinskii-Kosterlitz-Thouless transition in driven-dissipative condensates

We study the 2d phase transition of a driven-dissipative system of exciton-polaritons under non-resonant pumping. Stochastic calculations are used to investigate the Berezinskii-Kosterlitz-Thouless-like phase diagram for experimentally realistic parameters, with a special attention to the non-equilibrium features.Comment: 8 pages, 5 figures, plus supplementary information

Kibble-Zurek Mechanism in Driven Dissipative Systems Crossing a Nonequilibrium Phase Transition

The Kibble-Zurek mechanism constitutes one of the most fascinating and universal phenomena in the physics of critical systems. It describes the formation of domains and the spontaneous nucleation of topological defects when a system is driven across a phase transition exhibiting spontaneous symmetry breaking. While a characteristic dependence of the defect density on the speed at which the transition is crossed was observed in a vast range of equilibrium condensed matter systems, its extension to intrinsically driven dissipative systems is a matter of ongoing research. In this Letter, we numerically confirm the Kibble-Zurek mechanism in a paradigmatic family of driven dissipative quantum systems, namely exciton-polaritons in microcavities. Our findings show how the concepts of universality and critical dynamics extend to driven dissipative systems that do not conserve energy or particle number nor satisfy a detailed balance condition

Kibble-Zurek mechanism in driven-dissipative systems crossing a non-equilibrium phase transition

The Kibble-Zurek mechanism constitutes one of the most fascinating and universal phenomena in the physics of critical systems. It describes the formation of domains and the spontaneous nucleation of topological defects when a system is driven across a phase transition exhibiting spontaneous symmetry breaking. While a characteristic dependence of the defect density on the speed at which the transition is crossed was observed in a vast range of equilibrium condensed matter systems, its extension to intrinsically driven-dissipative systems is a matter of ongoing research. In this work we numerically confirm the Kibble-Zurek mechanism in a paradigmatic family of driven-dissipative quantum systems, namely exciton-polaritons in microcavities. Our findings show how the concepts of universality and critical dynamics extend to driven-dissipative systems that do not conserve energy or particle number nor satisfy a detailed balance condition