Effects of quadratic coupling and squeezed vacuum injection in an optomechanical cavity assisted with a Bose-Einstein condensate

TL;DR

This paper theoretically explores a hybrid optomechanical system with a BEC and a membrane, demonstrating enhanced quadrature squeezing and entanglement through quadratic coupling and squeezed vacuum injection, with tunable stability properties.

Contribution

It introduces a hybrid system with quadratic coupling and squeezed vacuum injection, showing improved squeezing, entanglement, and stability control without relying solely on squeezed light.

Findings

Strong quadrature squeezing in mechanical and BEC modes

High entanglement achievable without squeezed light

Quadratic coupling influences system stability and mode frequencies

Abstract

We investigate theoretically a hybrid system consisting of a Bose-Einstein condensate (BEC) trapped inside a laser driven membrane-in-the-middle optomechanical cavity assisted with squeezed vacuum injection whose moving membrane interacts both linearly and quadratically with the radiation pressure of the cavity. It is shown that such a hybrid system is very suitable for generating strong quadrature squeezing in the mechanical mode of the membrane and the Bogoliubov mode of the BEC in the unresolved sideband regime. More interestingly, by choosing a suitable sign for the quadratic optomechanical coupling (QOC) one can achieve a very high degree of squeezing in the mechanical mode and a strong entanglement between the mechanical and atomic modes without the necessity of using squeezed light injection. Furthermore, the QOC changes the effective oscillation frequencies of both the mechanical and the atomic modes and affects their relaxation times. It can also make the system switch form optical bistability to tristability