Nonreciprocal total cross section of quantum metasurfaces

TL;DR

This paper investigates how quantum metasurfaces composed of two-level atoms can exhibit significant nonreciprocal total cross sections, controlled by atomic positioning and transition frequencies, without needing a nonreciprocal environment.

Contribution

It demonstrates the possibility of achieving large nonreciprocal responses in quantum metasurfaces through atomic configuration and dark state population control.

Findings

Large nonreciprocal responses are achievable in quantum metasurfaces.

Control over atomic positions and transition frequencies is key.

Dark state population is critical for nonreciprocal effects.

Abstract

Nonreciprocity originating from classical interactions among nonlinear scatterers has been attracting increasing attention in the quantum community, offering a promising tool to control excitation transfer for quantum information processing and quantum computing. In this work, we explore the possibility of realizing largely nonreciprocal total cross sections for a pair of quantum metasurfaces formed by two parallel periodic arrays of two-level atoms. We show that large nonreciprocal responses can be obtained in such nonlinear systems by controlling the position of the atoms and their transition frequencies, without requiring that the environment in which the atoms are placed is nonreciprocal. We demonstrate the connection of this effect with the population of a slowly-decaying dark state, which is critical to obtain large nonreciprocal responses.