3 research outputs found
Non adiabatic features of electron pumping through a quantum dot in the Kondo regime
We investigate the behavior of the dc electronic current, Jdc, in an
interacting quantum dot driven by two ac local potentials oscillating with a
frequency, Omega0, and a phase-lag, phi. We provide analytical functions to
describe the fingerprints of the Coulomb interaction in an experimental Jdc vs
phi characteristic curve. We show that the Kondo resonance reduces at low
temperatures the frequency range for the linear behavior of Jdc in Omega0 to
take place and determines the evolution of the dc-current as the temperature
increases.Comment: 8 pages, 7 figure
Local density of states on a vibrational quantum dot out of equilibrium
We calculate the nonequilibrium local density of states on a vibrational
quantum dot coupled to two electrodes at T=0 using a numerically exact
diagrammatic Monte Carlo method. Our focus is on the interplay between the
electron-phonon interaction strength and the bias voltage. We find that the
spectral density exhibits a significant voltage dependence if the voltage
window includes one or more phonon sidebands. A comparison with
well-established approximate approaches indicates that this effect could be
attributed to the nonequilibrium distribution of the phonons. Moreover, we
discuss the long transient dynamics caused by the electron-phonon coupling.Comment: 9 pages, 11 figure
Long transient dynamics in the Anderson-Holstein model out of equilibrium
We calculate the time dependent nonequilibrium current through a single level
quantum dot strongly coupled to a vibrational mode. The nonequilibrium real
time dynamics caused by an instantaneous coupling of the leads to the quantum
dot is discussed using an approximate method. The approach, which is specially
designed for the strong polaronic regime, is based on the so-called polaron
tunneling approximation. Considering different initial dot occupations, we show
that a common steady state is reached after times much larger than the typical
electron tunneling times due to a polaron blocking effect in the dot charge. A
direct comparison is made with numerically exact data, showing good agreement
for the time scales accessible by the diagrammatic Monte Carlo simulation
method