Direct measurement of the optical trap-induced decoherence

TL;DR

This paper directly measures how optical trapping introduces decoherence in massive mechanical oscillators, revealing a fundamental limit that impacts future quantum mechanics experiments.

Contribution

It provides the first direct measurement of trap-induced decoherence, clarifying its role as a fundamental limit in optomechanical systems.

Findings

Optical trap increases decoherence via stochastic forces.

Measured decoherence rate is primarily due to optical trapping.

Results inform future quantum mechanics tests in optomechanics.

Abstract

Thermal decoherence is a major obstacle to the realization of quantum coherence for massive mechanical oscillators. Although optical trapping has been used to reduce the thermal decoherence rate for such oscillators, it also increases the rate by subjecting the oscillator to stochastic forces resulting from the frequency fluctuations of the optical field, thereby setting a fundamental limit on the reduction. This is analogous to the noise penalty in an active feedback system. Here, we directly measure the rethermalizaton process for an initially cooled and optically trapped suspended mirror, and identify the current limiting decoherence rate as due to the optical trap. Our experimental study of the trap-induced decoherence rate will enable future advances in the probing of fundamental quantum mechanics in the bad cavity regime, such as testing of deformed commutators.