Probing the quantum behaviors of a nanomechanical resonator coupled to a double quantum dot

TL;DR

This paper introduces a method using current correlation spectra of a quantum point contact to detect quantum behaviors and cooling of a nanomechanical resonator coupled to a double quantum dot, including backaction effects.

Contribution

It presents a novel approach to probe quantum states of a nanomechanical resonator via current correlation measurements in a coupled quantum dot system.

Findings

Quantum behaviors of NAMR can be observed through current correlation spectra.

The method allows examination of NAMR cooling into the quantum regime.

Coupling strength influences energy level shifts and measurement outcomes.

Abstract

We propose a current correlation spectrum approach to probe the quantum behaviors of a nanome-chanical resonator (NAMR). The NAMR is coupled to a double quantum dot (DQD), which acts as a quantum transducer and is further coupled to a quantum-point contact (QPC). By measuring the current correlation spectrum of the QPC, shifts in the DQD energy levels, which depend on the phonon occupation in the NAMR, are determined. Quantum behaviors of the NAMR could, thus, be observed. In particular, the cooling of the NAMR into the quantum regime could be examined. In addition, the effects of the coupling strength between the DQD and the NAMR on these energy shifts are studied. We also investigate the impacts on the current correlation spectrum of the QPC due to the backaction from the charge detector on the DQD.