Quantum backaction and noise interference in asymmetric two-cavity optomechanical systems

TL;DR

This paper investigates how cavity damping asymmetries in asymmetric two-cavity optomechanical systems influence quantum backaction and noise interference, enabling ground-state cooling and quantum non-demolition measurements under specific conditions.

Contribution

It reveals that cavity damping asymmetries induce dissipative optomechanical coupling and quantum noise interference, which can cancel backaction effects and facilitate advanced quantum measurements.

Findings

Quantum noise interference enables ground-state cooling in unresolved sideband regime.

Complete cancellation of linear backaction is possible in the bad-cavity limit.

Constraints on optomechanical coupling for QND measurements are established.

Abstract

We study the effect of cavity damping asymmetries on backaction in a "membrane-in-the-middle" optomechanical system, where a mechanical mode modulates the coupling between two photonic modes. We show that in the adiabatic limit, this system generically realizes a dissipative optomechanical coupling, with an effective position-dependent photonic damping rate. The resulting quantum noise interference can be used to ground-state cool a mechanical resonator in the unresolved sideband regime. We explicitly demonstrate how quantum noise interference controls linear backaction effects, and show that this interference persists even outside the adiabatic limit. For a one-port cavity in the extreme bad-cavity limit, the interference allows one to cancel all linear backaction effects. This allows continuous measurements of position-squared, with no stringent constraints on the single-photon optomechanical coupling strength. In contrast, such a complete cancellation is not possible in the good cavity limit. This places strict bounds on the optomechanical coupling required for quantum non-demolition measurements of mechanical energy, even in a one-port device.