Anomalous Point-Gap Interactions Unveil the Mirage Bath

TL;DR

This paper reveals a novel long-range interaction mechanism in open quantum systems mediated by a 'mirage bath' on a Riemann surface, demonstrating how non-Hermitian topology influences quantum dynamics and correlations.

Contribution

It uncovers a new interaction mechanism via a mirage bath that inherits the topology of a non-Hermitian system, expanding understanding of quantum interactions in dissipative environments.

Findings

Long-range interactions emerge despite localized photons within the gap.

Interactions are mediated by a virtual 'mirage bath' on a Riemann surface.

The mirage bath inherits the topology of the non-Hermitian system.

Abstract

Non-Hermitian topology has revolutionized our understanding of energy gaps and band topology, unveiling phases that do not exist within the Hermitian framework. Nonetheless, its fundamental implications for quantum interactions in open quantum systems remain largely unexplored. Here, we uncover a novel interaction mechanism by examining a quantum-optical system where quantum emitters interact through the photonic band-gap of a dissipative photon bath with periodic boundaries, described by a nonreciprocal Su-Schrieffer-Heeger model. Although localized photons within the gap should inhibit interactions between emitters in certain regimes, we find that long-range interactions emerge, defying conventional expectations. These anomalous interactions are mediated by a ``mirage bath" - a virtual bath that unfolds onto a distinct layer of the Riemann surface. This mirage bath generates emitter dynamics identical to those produced by the physical bath but possesses distinct band topology. Crucially, the interactions inherit the topology of the mirage bath, not the physical one. This bath duality is inherent to any dissipative bath with spectral topology, leading to a fundamentally new mechanism for long-range interactions and correlations across the multi-layered Riemann surface, unseen in traditional settings. Our findings open new avenues in quantum optics, many-body quantum simulations, and offer fresh insights into non-Hermitian topology.