Enhanced entanglement of two different mechanical resonators via coherent feedback

TL;DR

This paper demonstrates that adding a coherent feedback loop to an optomechanical system significantly enhances entanglement between two different mechanical resonators and extends the scheme's validity by effectively reducing cavity decay.

Contribution

It introduces a coherent feedback control method to improve and extend entanglement generation in optomechanical systems with two mechanical resonators.

Findings

Enhanced entanglement via feedback loop

Reduced effective cavity decay rate

Extended operational validity range

Abstract

It was shown [New J. Phys. 17, 103037 (2015)] that large and robust entanglement between two different mechanical resonators could be achieved, either dynamically or in the steady state, in an optomechanical system in which the two mechanical resonators are coupled to a single cavity mode driven by a suitably chosen two-tone field. An important limitation of the scheme is that the cavity decay rate must be much smaller than the two mechanical frequencies and their difference. Here we show that the entanglement can be remarkably enhanced, and the validity of the scheme can be largely extended, by adding a coherent feedback loop that effectively reduces the cavity decay rate.