Unconditional steady-state entanglement in macroscopic hybrid systems by coherent noise cancellation

TL;DR

This paper proposes a robust method for generating steady-state entanglement between two disparate oscillators in a cascaded setup, utilizing coherent noise cancellation and dynamical cooling, effective even in hot thermal environments.

Contribution

It introduces a generic, unconditional entanglement scheme for oscillators with different temperatures and decoherence, using cascaded quantum interference and noise cancellation techniques.

Findings

Achieves unconditional steady-state entanglement in macroscopic hybrid systems.

Performs comparably to conditional entanglement schemes when optimized.

Enhances entanglement robustness against thermal noise.

Abstract

The generation of entanglement between disparate physical objects is a key ingredient in the field of quantum technologies, since they can have different functionalities in a quantum network. Here we propose and analyze a generic approach to steady-state entanglement generation between two oscillators with different temperatures and decoherence properties coupled in cascade to a common unidirectional light field. The scheme is based on a combination of coherent noise cancellation and dynamical cooling techniques for two oscillators with effective masses of opposite signs, such as quasi-spin and motional degrees of freedom, respectively. The interference effect provided by the cascaded setup can be tuned to implement additional noise cancellation leading to improved entanglement even in the presence of a hot thermal environment. The unconditional entanglement generation is advantageous since it provides a ready-to-use quantum resource. Remarkably, by comparing to the conditional entanglement achievable in the dynamically stable regime, we find our unconditional scheme to deliver a virtually identical performance when operated optimally.