Correlation-induced resonances and population switching in a quantum dot coulomb valley

Strong correlation effects on electron transport through a spinless quantum dot are considered. When two single-particle levels in the quantum dot are degenerate, a conserved pseudospin degree of freedom appears for general tunneling matrix elements between the quantum dot and leads. Local fluctuations of the pseudospin in the quantum dot give rise to a pair of asymmetric conductance peaks near the center of a Coulomb valley. An exact relation to the population switching is provided.