Cooling a mechanical resonator via coupling to a tunable double quantum dot

TL;DR

This paper proposes a method to cool a mechanical resonator to its ground state by coupling it to a tunable double quantum dot, using microwave excitation and dynamical backaction, demonstrating experimental feasibility.

Contribution

It introduces a tunable double quantum dot system for resonator cooling, leveraging adjustable decay rates and detuning for effective ground state cooling.

Findings

Achieves steady-state occupancy below unity for the mechanical resonator.

Demonstrates that ground state cooling is experimentally feasible.

Shows analogy to laser sideband cooling in atomic physics.

Abstract

We study the cooling of a mechanical resonator (MR) that is capacitively coupled to a double quantum dot (DQD). The MR is cooled by the dynamical backaction induced by the capacitive coupling between the DQD and the MR. The DQD is excited by a microwave field and afterwards a tunneling event results in the decay of the excited state of the DQD. An important advantage of this system is that both the energy level splitting and the decay rate of the DQD can be well tuned by varying the gate voltage. We find that the steady average occupancy, below unity, of the MR can be achieved by changing both the decay rate of the excited state and the detuning between the transition frequency of the DQD and the microwave frequency, in analogy to the laser sideband cooling of an atom or trapped ion in atomic physics. Our results show that the cooling of the MR to the ground state is experimentally implementable.