Josephson relation for disordered superfluids

摘要: The Josephson sum rule relates the superfluid density to condensate order parameter via infrared residue of single-particle Green's function. We establish an effective relation for disordered condensates valid upon ensemble averaging. This has merit showing explicitly how superfluidity links coherent density, i.e., condensed particles with zero momentum. Detailed agreement is reached perturbation theory weak disorder.