Quadrature squeezing enhances Wigner negativity in a mechanical Duffing oscillator

TL;DR

This paper demonstrates that initial motional squeezing can significantly enhance Wigner negativity in a mechanical Duffing oscillator, aiding the generation of macroscopic non-classical states despite decoherence.

Contribution

It introduces a method using motional squeezing to effectively boost anharmonicity and generate quantum negativity in mechanical systems, addressing decoherence challenges.

Findings

Squeezing increases the rate of negativity generation.

Strong squeezing suppresses energy damping effects.

Good approximations of the Wigner function are possible at large squeezing.

Abstract

Generating macroscopic non-classical quantum states is a long-standing challenge in physics. Anharmonic dynamics is an essential ingredient to generate these states, but for large mechanical systems, the effect of the anharmonicity tends to become negligible compared to decoherence. As a possible solution to this challenge, we propose to use a motional squeezed state as a resource to effectively enhance the anharmonicity. We analyze the production of negativity in the Wigner distribution of a quantum anharmonic resonator initially in a squeezed state. We find that initial squeezing enhances the rate at which negativity is generated. We also analyze the effect of two common sources of decoherence, namely energy damping and dephasing, and find that the detrimental effects of energy damping are suppressed by strong squeezing. In the limit of large squeezing, which is needed for state-of-the-art systems, we find good approximations for the Wigner function. Our analysis is significant for current experiments attempting to prepare macroscopic mechanical systems in genuine quantum states. We provide an overview of several experimental platforms featuring nonlinear behaviors and low levels of decoherence. In particular, we discuss the feasibility of our proposal with carbon nanotubes and levitated nanoparticles.