# Manipulation and enhancement of asymmetric steering via interference effects induced by closed-loop coupling

## TL;DR

This paper introduces a phase control method in a three-mode system with closed-loop coupling to generate asymmetric, directional quantum steering and entanglement, enhancing robustness against thermal noise through interference effects.

## Contribution

It presents a novel interference-based approach to manipulate asymmetric steering in symmetric systems without introducing losses or noise asymmetrically.

## Key findings

- Directional steering achieved via phase-controlled interference.
- Entanglement and steering are enhanced and made more robust.
- Interference effects enable control over correlations in multipartite systems.

## Abstract

We present a phase control method for a general three-mode system with closed-loop in coupling that drives the system into an entangled steady state and produces directional steering between two completely symmetric modes via quantum interference effects. In the scheme, two modes are coupled with each other both by a direct binary interaction and by an indirect interaction through a third intermediate damping mode, creating interference effects determined by the relative phase between the two physical interaction paths. By calculating the populations and correlations of the two modes, we show that depending on the phase, two modes can be prepared into an entangled steady state with asymmetric and directional steering even if they possess completely symmetric decoherence properties. Meanwhile, entanglement and steering can be significantly enhanced due to constructive interference, and thus more robust to thermal noises. This provides an active method to manipulate the asymmetry of steering instead of adding asymmetric losses or noises on subsystems at the cost of reducing steerability. Moreover, we show that the interference effects can also enhance and control the correlations between other pair of modes in the loop with opposite phase dependent behavior, indicating monogamy constraints for distributing correlations among multipartite. The present model could be applied in cavity optomechanical systems or in antiferromagnets where all components can mutually interact.