Drag in a resonantly driven polariton fluid

Abstract

We study the linear response of a coherently driven polariton fluid in the pump-only configuration scattering against a point-like defect and evaluate analytically the drag force exerted by the fluid on the defect. When the system is excited near the bottom of the lower polariton dispersion, the sign of the interaction-renormalised pump detuning classifies the collective excitation spectra in three different categories [C. Ciuti and I. Carusotto, physica status solidi (b) 242, 2224 (2005)]: linear for zero, diffusive-like for positive, and gapped for negative detuning. We show that both cases of zero and positive detuning share a qualitatively similar crossover of the drag force from the subsonic to the supersonic regime as a function of the fluid velocity, with a critical velocity given by the speed of sound found for the linear regime. In contrast, for gapped spectra, we find that the critical velocity exceeds the speed of sound. In all cases, the residual drag force in the subcritical regime depends on the polariton lifetime only. Also, well below the critical velocity, the drag force varies linearly with the polariton lifetime, in agreement with previous work [E. Cancellieri et al., Phys. Rev. B 82, 224512 (2010)], where the drag was determined numerically for a finite-size defect.

7 pages, 2 figures

References in corpus (5)

• Observation of Superfluidity of Polaritons in Semiconductor Microcavities
• Non-equilibrium quantum condensation in an incoherently pumped dissipative system
• Light Engineering of the Polariton Landscape in Semiconductor Microcavities
• Hydrodynamic nucleation of vortices and solitons in a resonantly excited polariton superfluid
• Superflow of resonantly driven polaritons against a defect