Spin relaxation in a polariton fluid: Quantum hydrodynamic approach
Phys. Rev. B 113, 134513 – Published 10 April, 2026
DOI: https://doi.org/10.1103/schp-qjmz
Abstract
We present a generalized mean-field description of spinor polariton fluids and introduce a model that incorporates pure energy relaxation, while conserving particle number. This model constitutes the spinor extension of our quantum-hydrodynamic theory, enabling a consistent treatment of two-component condensates with polarization (pseudospin) degrees of freedom. Starting from a two-component hydrodynamic formulation, we derive a closed set of equations in which pure energy relaxation acts through both the usual density/phase and spin (polarization) channels. We show how these relaxation pathways govern polarization dynamics, determine the stability of stationary polarized states, and modify the spectrum of elementary excitations, with particular emphasis on a condensate in an external magnetic field. Although we focus on exciton-polaritons in semiconductor microcavities, our approach can be applied to other spinor bosonic condensates where spin relaxation plays a significant role.
