Cooling a nanomechanical resonator by a triple quantum dot

TL;DR

This paper proposes a method to cool a nanomechanical resonator to its ground state using a triple quantum dot system that exploits quantum interference effects to facilitate energy transfer from the resonator.

Contribution

It introduces a novel cooling scheme employing a triple quantum dot in a $ ext{Lambda}$ configuration to achieve ground-state cooling of a nanomechanical resonator.

Findings

Ground-state cooling is theoretically achievable with the proposed scheme.

Quantum interference in the TQD enables trapping electrons in a dark state.

The method allows repeated energy absorption from the resonator by electrons.

Abstract

We propose an approach for achieving ground-state cooling of a nanomechanical resonator (NAMR) capacitively coupled to a triple quantum dot (TQD). This TQD is an electronic analog of a three-level atom in $\Lambda$ configuration which allows an electron to enter it via lower-energy states and to exit only from a higher-energy state. By tuning the degeneracy of the two lower-energy states in the TQD, an electron can be trapped in a dark state caused by destructive quantum interference between the two tunneling pathways to the higher-energy state. Therefore, ground-state cooling of an NAMR can be achieved when electrons absorb readily and repeatedly energy quanta from the NAMR for excitations.