Fermi distribution of semicalssical non-eqilibrium Fermi states
  When a classical device suddenly perturbs a degenerate Fermi gas a semiclassical non-equilibrium Fermi state arises. Semiclassical Fermi states are characterized by a Fermi energy or Fermi momentum that slowly depends on space or/and time. We show that the Fermi distribution of a semiclassical Fermi state has a universal nature. It is described by Airy functions regardless of the details of the perturbation. In this letter we also give a general discussion of coherent Fermi states. 
Eldad Bettelheim, Paul B. Wiegmann
cond-mat.quant-gas cond-mat.mes-hall