Fermi-Bose Correspondence at Finite Temperature

The correspondence between fermi-sea/bose-condensate displacements and the number-conserving product of two fermi/bose fields is generalised to finite temperatures. It is shown that the straightforward generalisation that involves making the sea-bosons participate in the thermodynamic averaging does not work out. A remedy is found which involves treating the sea-displacement bosons at zero temperature while all finite temperature effects have to be lumped into the coefficients. We also show that all the finite temperature dynamical four-point and six-point functions come out correctly as do some of the commutation rules involving the fermion/boson product that go through unscathed. It is also shown that this unusual prescription of leaving out the sea-bosons from the thermodynamic averaging does in fact reproduce the correct RPA dielectric function at finite temperature. This article is not however, critic-proof.