Long-range quantum emitter interactions mediated by a non-local metasurface: Application to qubit-qubit entanglement

TL;DR

This paper proposes using non-local metasurfaces supporting bound-states-in-the-continuum to enable long-range, efficient quantum emitter interactions and entanglement, surpassing free-space limitations.

Contribution

Introduction of a metasurface platform supporting high $eta$-factors for scalable, long-range quantum emitter interactions and entanglement generation.

Findings

$eta$-factors can exceed 80% without mode engineering

Entanglement develops faster and is amplified over free space

Effective for large 2D quantum emitter arrays

Abstract

Scalable quantum technologies demand long-range interactions between many distant quantum emitters (QEs). We introduce non-local metasurfaces supporting bound-states-in-the-continuum (BICs) as a promising platform to achieve this goal. We show that efficient QE interactions depend almost entirely on emitter-BIC coupling efficiencies ($\beta$-factors), which in our system can exceed $80\%$ even without additional mode engineering. These values rival those of 1D waveguides but are achieved here in a geometry that naturally accommodates large 2D QE arrays. Using this platform, we explore entanglement generation between two remote QEs, finding that it develops faster than in free space, is significantly amplified, and persists over separations spanning several emission wavelengths. Optimal inter-QE interactions require large $\beta$-factors but only moderately small Purcell factors, both within experimentally achievable ranges. Our results establish non-local metasurfaces as a practical and scalable platform for leading-edge quantum nanophotonics.