  One of the goals of pump/probe spectroscopies is to determine how electrons
relax after they have been driven out of equilibrium. It is challenging to
determine how close electrons are to a thermal state solely by fitting their
distribution to a Fermi-Dirac distribution. Instead, we propose that one
compare the effective temperatures of both fermions and collective bosonic
modes (derived from the fermions) to determine the distance from a thermal
state. Measurements of effective fermionic and bosonic temperatures can be
achieved directly via photoemission and nonresonant Raman scattering. Their
difference quantifies the distance from thermal equilibrium.
