Arbitrarily large steady-state bosonic squeezing via dissipation

TLDR

Coherent feedback via minimally perturbing a quantum nondemolition measurement of a single mechanical quadrature provides a framework for steady‑state squeezing. The study proposes and analyzes a two‑laser scheme to achieve large steady‑state squeezing of a mechanical resonator, optimizing parameters and outlining detection through the cavity output. The approach employs a dissipative reservoir engineered by a driven cavity, avoiding explicit measurement or optical spring modulation. The results show a close link between coherent feedback and reservoir engineering and demonstrate that the scheme is broadly applicable, including to superconducting circuits.

Abstract

We discuss how large amounts of steady-state quantum squeezing (beyond 3 dB) of a mechanical resonator can be obtained by driving an optomechanical cavity with two control lasers with differing amplitudes. The scheme does not rely on any explicit measurement or feedback, nor does it simply involve a modulation of an optical spring constant. Instead, it uses a dissipative mechanism with the driven cavity acting as an engineered reservoir. It can equivalently be viewed as a coherent feedback process, obtained by minimally perturbing the quantum nondemolition measurement of a single mechanical quadrature. This shows that in general the concepts of coherent feedback schemes and reservoir engineering are closely related. We analyze how to optimize the scheme, how the squeezing scales with system parameters, and how it may be directly detected from the cavity output. Our scheme is extremely general, and could also be implemented with, e.g., superconducting circuits.