Large cooperativity and microkelvin cooling with a three-dimensional optomechanical cavity

TL;DR

This paper demonstrates a silicon nitride membrane coupled to a 3D superconducting microwave cavity achieving extremely high cooperativity and microkelvin cooling, paving the way for quantum superposition states of mechanical motion.

Contribution

The authors introduce a novel optomechanical architecture with record-high cooperativity and lowest temperature cooling, advancing towards quantum regime control.

Findings

Achieved an optomechanical cooperativity of 146,000.

Performed sideband cooling to 34±5 μK, the lowest reported.

Cooling limited by classical noise, with potential for ground-state cooling.

Abstract

In cavity optomechanics, light is used to control mechanical motion. A central goal of the field is achieving single-photon strong coupling, which would enable the creation of quantum superposition states of motion. Reaching this limit requires significant improvements in optomechanical coupling and cavity coherence. Here we introduce an optomechanical architecture consisting of a silicon nitride membrane coupled to a three-dimensional superconducting microwave cavity. Exploiting their large quality factors, we achieve an optomechanical cooperativity of 146,000 and perform sideband cooling of the kilohertz-frequency membrane motion to 34$\pm$5 $\mu$K, the lowest mechanical mode temperature reported to date. The achieved cooling is limited only by classical noise of the signal generator, and should extend deep into the ground state with superconducting filters. Our results suggest that this realization of optomechanics has the potential to reach the regimes of ultra-large cooperativity and single-photon strong coupling, opening up a new generation of experiments.