Long-range interactions in Weyl dense atomic arrays protected from dissipation and disorder

TL;DR

This paper introduces a novel atomic array platform that leverages Weyl points to enable long-range, robust, and decoherence-free quantum interactions, overcoming limitations of traditional photonic systems.

Contribution

It demonstrates how to engineer Weyl points in atomic arrays to achieve topologically protected, long-range quantum interactions that are immune to disorder and decoherence.

Findings

Weyl points can be designed in atomic metamaterials to mediate long-range interactions.

Topological protection ensures robustness against disorder and decoherence.

Fermi arc surface states enable non-reciprocal atomic interactions.

Abstract

Long-range interactions are a key resource in many quantum phenomena and technologies. Free-space photons mediate power-law interactions but lack tunability and suffer from decoherence processes due to their omnidirectional emission. Engineered dielectrics can yield tunable and coherent interactions, but typically at the expense of making them both shorter-ranged and sensitive to material disorder and photon loss. Here, we propose a platform that can circumvent all these limitations based on three-dimensional subwavelength atomic arrays subjected to magnetic fields. Our key result is to show how to design the polaritonic bands of these atomic metamaterials to feature a pair of frequency-isolated Weyl points. These Weyl excitations can thus mediate interactions that are simultaneously long-range, due to their gapless nature; robust, due to the topological protection of Weyl points; and decoherence-free, due to their subradiant character. We demonstrate the robustness of these isolated Weyl points for a large regime of interatomic distances and magnetic field values and characterize the emergence of their corresponding Fermi arcs surface states. The latter can as well lead to two-dimensional, non-reciprocal atomic interactions with no analogue in other chiral quantum optical setups.