Order parameter dynamics of a Bose-Einstein condensate of exciton-polaritons in semiconductor microcavities

TL;DR

This paper theoretically demonstrates that Bose-Einstein condensation of exciton-polaritons in semiconductor microcavities leads to spontaneous linear polarization buildup, with polarization properties serving as an order parameter for the phase transition.

Contribution

It introduces the linear polarization degree as a new order parameter for polariton Bose condensation and analyzes polarization dynamics under spin degeneracy lifting.

Findings

Spontaneous linear polarization appears in the emission spectra.

Elliptically polarized light emerges when spin degeneracy is lifted.

Polarization decay is influenced by polariton interactions and state statistics.

Abstract

It is shown theoretically that Bose condensation of spin-degenerated exciton-polaritons results in spontaneous buildup of the linear polarization in emission spectra of semiconductor microcavities. The linear polarization degree is a good order parameter for the polariton Bose condensation. If spin-degeneracy is lifted, an elliptically polarized light is emitted by the polariton condensate. The main axis of the ellipse rotates in time due to self-induced Larmor precession of the polariton condensate pseudospin. The polarization decay time is governed by the dephasing induced by the polariton-polariton interaction and strongly depends on the statistics of the condensed state.