Simulating electron-vibron energy transfer with quantum dots and resonators

TL;DR

This paper explores simulating electron-vibron energy transfer using quantum dots coupled to microwave resonators, analyzing energy transfer mechanisms and interference effects with theoretical models.

Contribution

It introduces a method to extend quantum dot simulators to include molecular vibrational modes via resonators and compares two theoretical approaches for analysis.

Findings

Identifies a gate-tunable interference effect affecting charge and energy transfer.

Shows a minimum in charge current correlates with a maximum in energy transfer.

Analyzes the merits and shortcomings of Lindblad and Keldysh methods.

Abstract

Gateable semiconductor quantum dots (QDs) provide a versatile platform for analog quantum simulations of electronic many-body systems. In particular, QD arrays offer a natural representation of the interacting $\pi$-electron system of small hydrocarbons. Here we investigate the prospects for extending QD simulators to encompass also the nuclear degrees of freedom. We represent the molecular vibrational modes by single-mode microwave resonators coupled capacitively to the QDs and study the gate-tunable energy transfer from a voltage-biased triple quantum dot (TQD) system to a single damped resonator mode. We determine the QD population inversions, the corresponding charge and energy currents as well as the resonator photon number, using Lindblad master equations and lowest-order perturbation theory within Keldysh Green function formalism. Along the way, we discuss the merits and shortcomings of the two methods.A central result is the interrelation of a pronounced minimum in the charge current with a maximum in energy transfer, arising from a gate-tunable interference effect in the molecular orbitals of the TQD electron system.