Measurement-feedback control of chiral photon emission from an atom chain into a nanofiber

TL;DR

This paper explores how measurement-based feedback control can manipulate chiral photon emission and the steady state of a laser-driven atomic chain coupled to a nanofiber, offering insights for quantum light-matter network engineering.

Contribution

It introduces a feedback scheme that controls photon emission directionality and many-body states in an atom chain coupled to a nanofiber, advancing quantum network control methods.

Findings

Feedback influences photon counting rates.

Feedback modifies the quadratures of the emitted light.

Steady states are controllable via feedback parameters.

Abstract

We theoretically investigate measurement-based feedback control of a laser-driven one-dimensional atomic chain interfaced with a nanofiber. The interfacing leads to all-to-all interactions among the atomic emitters and induces chirality, i.e. the directional emission of photons into a preferred guided mode of the nanofiber. In the setting we consider, the measurement of guided light -- conducted either by photon counting or through homodyne detection of the photocurrent quadratures -- is fed back into the system through a modulation of the driving laser field. We investigate how this feedback scheme influences the photon counting rate and the quadratures of the guided light field. Moreover, we analyse how feedback alters the many-body steady state of the atom chain. Our results provide some insights on how to control and engineer dynamics in light-matter networks realizable with state-of-the-art experimental setups.