Semiclassical analysis of the nonequilibrium local polaron.
A resonant level strongly coupled to a local phonon under nonequilibrium conditions is investigated. The nonequilibrium Hartree-Fock approximation is shown to correspond to approximating the steady state density matrix by delta functions at field values to which the local dynamics relaxes in a semiclassical limit. If multiple solutions exist, all are shown to make nonvanishing contributions to physical quantities: multistability does not exist. Departures from equilibrium are shown to produce decoherence, preventing the formation of a polaron feature in the spectral function. The formalism also applies to the nonequilibrium Kondo problem.
Mitra
A
A
Department of Physics, Columbia University, 538 West 120th Street, New York, New York 10027, USA.
Aleiner
I
I
Millis
A J
AJ