Thermodynamic Potential and Drag Force of the Impurity-Polariton Many-Body Interaction

Investigating the many-body interaction among polaritons is a fundamental goal in comprehending nonlinear behaviors in microcavity semiconductor systems. Hence, the present study focuses on exploring the many-body interaction between excitons and impurities. It was observed that the energy eigenequation governing this system is of sixth-order, rendering it unsolvable. Consequently, a strategy involving the utilization of impurity weight was employed to partition the initial energy eigenequation into two fourth-order equations, a method deemed suitable for lower order approximations. Subsequently, Green’s function was applied to these two fourth-order equations. The analysis of the computed results, encompassing the energy spectrum, polariton density, and thermodynamic potential of the system, reveals that the many-body interaction between excitons and impurities induces the emergence of novel bound states of quasiparticles. Moreover, the inclusion of impurities leads to a decrease in both energy and density of polaritons. Furthermore, the investigation delves into the drag force exerted by impurities on excitons, demonstrating that the drag force escalates in a second-order fashion with impurity velocity and persists even as impurity velocity increases, surpassing the Landau’s equilibrium theory.