  We study spin-dependent heat transport in quantum gases, focusing on
transport phenomena related to pure spin currents and spin-dependent
temperatures. Using the Boltzmann equation, we compute the coupled spin and
heat transport coefficients as a function of temperature and interaction
strength for energy dependent $s$-wave scattering. We address the issue of
whether spin-dependent temperatures can be sustained on a time and length scale
relevant for experiments by computing the spin-heat relaxation time and
diffusion length. We find that the time scale for spin-heat relaxation time
diverges at low temperatures for both bosons and fermions, indicating that the
concept of spin-heat accumulation is well defined for degenerate gases. For
bosons, we find power-law behavior on approach to Bose condensation above the
critical temperature, as expected from the theory of dynamical critical
phenomena.
