Kerr enhanced backaction cooling in magnetomechanics

TL;DR

This paper introduces a novel nonlinear cavity approach that significantly enhances backaction cooling of low-frequency mechanical oscillators, surpassing traditional limits and enabling broader applications in quantum sensing and fundamental physics.

Contribution

The study demonstrates experimentally that a nonlinear cavity can outperform linear systems in backaction cooling and predicts surpassing the standard cooling limit.

Findings

Achieved over tenfold improvement in cooling efficiency compared to linear systems.

Experimental validation of nonlinear cavity cooling surpassing linear system performance.

Theoretical prediction of exceeding the standard cooling limit with nonlinear cavities.

Abstract

Optomechanics is a prime example of light matter interaction, where photons directly couple to phonons, allowing to precisely control and measure the state of a mechanical object. This makes it a very appealing platform for testing fundamental physics or for sensing applications. Usually, such mechanical oscillators are in highly excited thermal states and require cooling to the mechanical ground state for quantum applications, which is often accomplished by utilising optomechanical backaction. However, while massive mechanical oscillators are desirable for many tasks, their frequency usually decreases below the cavity linewidth, significantly limiting the methods that can be used to efficiently cool. Here, we demonstrate a novel approach relying on an intrinsically nonlinear cavity to backaction-cool a low frequency mechanical oscillator. We experimentally demonstrate outperforming an identical, but linear, system by more than one order of magnitude. Furthermore, our theory predicts that with this approach we can also surpass the standard cooling limit of a linear system. By exploiting a nonlinear cavity, our approach enables efficient cooling of a wider range of optomechanical systems, opening new opportunities for fundamental tests and sensing.