  Using a real-time renormalization group method we study the minimal model of
a quantum dot dominated by charge fluctuations, the two-lead interacting
resonant level model, at finite bias voltage. We develop a set of RG equations
to treat the case of weak and strong charge fluctuations, together with the
determination of power-law exponents up to second order in the Coulomb
interaction. We derive analytic expressions for the charge susceptibility, the
steady-state current and the conductance in the situation of arbitrary system
parameters, in particular away from the particle-hole symmetric point and for
asymmetric Coulomb interactions. In the generic asymmetric situation we find
that power laws can be observed for the current only as function of the level
position (gate voltage) but not as function of the voltage. Furthermore, we
study the quench dynamics after a sudden switch-on of the level-lead couplings.
The time evolution of the dot occupation and current is governed by exponential
relaxation accompanied by voltage-dependent oscillations and characteristic
algebraic decay.
