Local density of states on a vibrational quantum dot out of equilibrium

TL;DR

This paper uses a numerically exact Monte Carlo method to study how electron-phonon interactions affect the local density of states in a vibrational quantum dot out of equilibrium, revealing voltage-dependent spectral features.

Contribution

It provides the first detailed analysis of nonequilibrium local density of states on a vibrational quantum dot considering strong electron-phonon coupling using a numerically exact approach.

Findings

Spectral density depends significantly on bias voltage when phonon sidebands are within the voltage window.

Nonequilibrium phonon distribution influences the spectral features.

Long transient dynamics are observed due to electron-phonon interactions.

Abstract

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.