Ground state cooling of a nanomechanical resonator in the weak-confinement regime via quantum interference

TL;DR

This paper proposes a quantum interference method to achieve ground state cooling of a nanomechanical resonator coupled to a superconducting flux qubit, even in the weak-confinement regime, enabling faster and more efficient cooling.

Contribution

The authors introduce a novel interference-based cooling scheme that cancels detrimental excitations, allowing ground state cooling in regimes previously considered challenging.

Findings

Ground state cooling is achievable in the weak-confinement regime.

Quantum interference cancels unwanted carrier excitations.

The scheme enables fast and efficient cooling with strong fields.

Abstract

Ground state cooling of a nanomechanical resonator coupled to a superconducting flux qubit is discussed. We show that by inducing quantum interference to cancel detrimental carrier excitations, ground state cooling becomes possible in the weak-confinement or non-resolved regime. The qubit is modelled as a three-level system in lambda configuration, and the driving fluxes are applied such that the qubit absorption spectrum exhibits electromagnetically induced transparency, thereby cancelling the unwanted carrier excitation. As our interference-based scheme allows to apply strong cooling fields, fast and efficient cooling can be achieved.