Electron transport through a quantum dot assisted by cavity photons

TL;DR

This study explores how cavity photons influence electron transport through a quantum dot, revealing photon-assisted tunneling effects and the impact of photon polarization on transport characteristics.

Contribution

It introduces a non-Markovian density-matrix approach to analyze transient electron transport with full electron-photon interactions in a quantum dot system.

Findings

Photon-assisted transport peaks appear with x-polarized photons.

Photon polarization affects the transport due to system anisotropy.

Coherent inelastic scattering to two-photon states is possible with initial cavity photons.

Abstract

We investigate transient transport of electrons through a single-quantum-dot controlled by a plunger gate. The dot is embedded in a finite wire that is weakly coupled to leads and strongly coupled to a single cavity photon mode. A non-Markovian density-matrix formalism is employed to take into account the full electron-photon interaction in the transient regime. In the absence of a photon cavity, a resonant current peak can be found by tuning the plunger gate voltage to lift a many-body state of the system into the source-drain bias window. In the presence of an $x$-polarized photon field, additional side peaks can be found due to photon-assisted transport. By appropriately tuning the plunger-gate voltage, the electrons in the left lead are allowed to make coherent inelastic scattering to a two-photon state above the bias window if initially one photon was present in the cavity. However, this photon-assisted feature is suppressed in the case of a $y$-polarized photon field due to the anisotropy of our system caused by its geometry.