Engineering squeezed thermal reservoirs via passive linear coupling

TL;DR

This paper presents a passive, linear coupling method to engineer squeezed thermal reservoirs, simplifying experimental setups and enabling advanced quantum thermodynamics and information processing applications.

Contribution

It introduces a general framework for reservoir engineering using only time-independent linear coupling, avoiding complex active controls or squeezed inputs.

Findings

Framework applicable across various quantum platforms.

Enables dissipative squeezing without active control.

Facilitates decoherence suppression and entanglement stabilization.

Abstract

Squeezed thermal reservoirs, characterized by thermal noise with anisotropic fluctuations, have profound implications in quantum thermodynamics and serve as powerful resources for quantum information. However, their experimental realizations remain challenging. Existing schemes typically rely on injected squeezed light, time-dependent modulation, or driven nonlinear interactions, which introduce complexity and limit experimental feasibility. Using only time-independent linear coupling to a lossy mode within a normal thermal environment, we identify a general and experimentally accessible framework for squeezed-reservoir engineering, applicable across platforms such as circuit and cavity quantum electrodynamics as well as coupled cavity systems. We illustrate the framework through two experimentally relevant cases: directional phase coherence extension in two-level systems like qubits or atoms, and dissipative quadrature squeezing in bosonic modes like photons or phonons. By eliminating the need for active control or squeezed input, our passive linear-coupling approach provides a resource-efficient and practical pathway to dissipative squeezing, decoherence suppression, entanglement stabilization, quantum simulation, and the exploration of unconventional quantum thermodynamics and phase transitions.