A density-functional theory is established for inhomogeneous superfluids at
finite temperature, subject to time-dependent external fields in isothermal
conditions. After outlining parallelisms between a neutral superfluid and a
charged superconductor, Hohenberg-Kohn-Sham-type theorems are proved for
gauge-invariant densities and a set of Bogolubov-Popov equations including
exchange and correlation is set up. Earlier results applying in the linear
response regime are recovered.Comment: 12 pages. Europhysics Letters, in pres
