Shortcuts to Squeezed Thermal States

TL;DR

This paper presents methods to generate squeezed thermal states in harmonic systems with controlled squeezing parameters and temperature, using reverse-engineered protocols for both unitary and open dynamics, including dissipation control via stochastic processes.

Contribution

It introduces novel protocols for fast and controlled generation of squeezed thermal states in arbitrary time, incorporating dissipation control through stochastic processes.

Findings

Protocols enable controlled squeezing and temperature in arbitrary time.

Dissipation control via stochastic processes allows fast thermalization.

Methods applicable to both unitary and open quantum dynamics.

Abstract

Squeezed state in harmonic systems can be generated through a variety of techniques, including varying the oscillator frequency or using nonlinear two-photon Raman interaction. We focus on these two techniques to drive an initial thermal state into a final squeezed thermal state with controlled squeezing parameters -- amplitude and phase -- in arbitrary time. The protocols are designed through reverse engineering for both unitary and open dynamics. Control of the dissipation is achieved using stochastic processes, readily implementable via, e.g., continuous quantum measurements. Importantly, this allows controlling the state entropy and can be used for fast thermalization. The developed protocols are thus suited to generate squeezed thermal states at controlled temperature in arbitrary time.