Effects of Quadratic Optomechanical Coupling on Bipartite Entanglements, Mechanical Ground-State Cooling and Squeezing in an Electro-Optomechanical System

TL;DR

This paper theoretically demonstrates how quadratic optomechanical coupling enhances bipartite entanglement, ground-state cooling, and squeezing in a hybrid electro-optomechanical system, with potential applications in quantum sensing and information processing.

Contribution

It reveals the beneficial effects of quadratic optomechanical coupling on entanglement, cooling, and squeezing, highlighting optimal conditions for these quantum features.

Findings

Enhanced bipartite entanglement by about 100 times at 1mK.

Mechanical ground-state cooling improved by approximately 10 times.

Mechanical quadrature squeezing exceeded 15 dB.

Abstract

We theoretically investigate the steady-state bipartite entanglements, mechanical ground-state cooling, and mechanical quadrature squeezing in a hybrid electro-optomechanical system where a moving membrane is linearly coupled to the microwave field mode of an LC circuit, while it simultaneously interacts both linearly and quadratically with the radiation pressure of a single-mode optical cavity. We show that by choosing a suitable sign and amplitude for the quadratic optomechanical coupling (QOC), one can achieve enhanced and thermally robust stationary bipartite entanglement between the subsystems, improved mechanical ground-state cooling, and Q-quadrature squeezing of the mechanical mode beyond the 3-dB limit of squeezing. In particular, we find that in the presence of QOC with negative sign and in the resolved sideband regime the bipartite optical-mechanical entanglement can be increased by about 2 order of magnitude around the temperature of 1mK, and it can be preserved against thermal noise up to the ambient temperature of 0.1K. Furthermore, the QOC with positive sign can give rise to the enhancement of the mechanical ground-state cooling by about 1 order of magnitude in the optical and microwave red-detuned regime. We also find that for the positive sign of QOC and near the microwave resonance frequency the squeezing degree of the Q-quadrature of the mechanical mode can be amplified up to 15 dB. Such a hybrid electro-optomechanical system can serve as a promising platform to engineer an improved entangled source for quantum sensing as well as quantum information processing.