  We investigate non-equilibrium transport properties of a quantum dot in the
Coulomb blockade regime under the condition of negligible inelastic scattering
during the dwelling time of the electrons in the dot. Using the quantum kinetic
equation we show that the absence of thermalization leads to a double-step in
the distribution function of electrons on the dot, provided that it is
symmetrically coupled to the leads. This drastically changes nonlinear
transport through the dot resulting in an additional (compared to the
thermalized case) jump in the conductance at voltages close to the charging
energy, which could serve as an experimental manifestation of the absence of
thermalization.
