  A Wigner-Klein-Kramers equation is proposed, which merges relativistic,
quantum and thermo dynamics. The relativistic effect on quantum Brownian motion
is studied via the Breit-Fermi Hamiltonian applied into a dissipative Madelung
hydrodynamics. A new thermo-quantum Smoluchowski equation is derived, which
accounts for the relativistic correction of the Bohm quantum potential.
