Approaching the motional ground state of a 10 kg object

TL;DR

This paper demonstrates cooling a 10 kg mechanical oscillator close to its quantum ground state, enabling future tests of quantum mechanics and gravity at large mass scales.

Contribution

The authors achieve near-ground-state cooling of a 10 kg object, a significant advancement in macroscopic quantum state preparation.

Findings

Reduced temperature to 77 nK from room temperature.

Suppressed quantum back-action by feedback by 11 orders of magnitude.

Prepared a 10 kg object with an average phonon occupation of 10.8.

Abstract

The motion of a mechanical object -- even a human-sized object -- should be governed by the rules of quantum mechanics. Coaxing them into a quantum state is, however, difficult: the thermal environment masks any quantum signature of the object's motion. Indeed, the thermal environment also masks effects of proposed modifications of quantum mechanics at large mass scales. We prepare the center-of-mass motion of a 10 kg mechanical oscillator in a state with an average phonon occupation of 10.8. The reduction in temperature, from room temperature to 77 nK, is commensurate with an 11 orders-of-magnitude suppression of quantum back-action by feedback -- and a 13 orders-of-magnitude increase in the mass of an object prepared close to its motional ground state. This begets the possibility of probing gravity on massive quantum systems.