Effect of quasiparticles injection on the ac response of a superconductor

We calculate the ac linear response of a superconductor in a nonequilibrium electronic state. The nonequilibrium state is produced by injecting quasiparticles into the superconductor from normal leads through asymmetric tunnel contacts. The dissipative part of the response is proportional to the total density of the injected quasiparticles regardless of the imbalance between the numbers of electronlike and holelike excitations. At fixed quasiparticle density, the lower their effective temperature, the stronger is the dissipation.