Josephson relation for disordered superfluids

Abstract

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

4 pages; v2: minor corrections, published version

References in corpus (4)

• Bose-Einstein-condensed systems in random potentials
• Bogoliubov Excitations of Disordered Bose-Einstein Condensates
• Thermodynamic Evidence for Nanoscale Bose-Einstein Condensation in ^4He Confined in Nanoporous Media
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