Title: Abrupt disappearance and reemergence of the SU(2) and SU(4) Kondo effects due to population inversion,
Abstract: The interplay of almost degenerate levels in quantum dots and molecular
junctions with possibly different couplings to the reservoirs has lead to many
observable phenomena, such as the Fano effect, transmission phase slips and the
SU(4) Kondo effect. Here we predict a dramatic repeated disappearance and
reemergence of the SU(4) and anomalous SU(2) Kondo effects with increasing gate
voltage. This phenomenon is attributed to the level occupation switching which
has been previously invoked to explain the universal transmission phase slips
in the conductance through a quantum dot. We use analytical arguments and
numerical renormalization group calculations to explain the observations and
discuss their experimental relevance and dependence on the physical parameters.