Coherent Control of Collective Spontaneous Emission through Self-interference

TL;DR

This paper introduces a novel method to coherently control collective spontaneous emission in quantum systems using self-interference effects in a nonlinear waveguide, enabling dynamic modulation of emission rates.

Contribution

It proposes a new scheme leveraging self-interference via photon backward scattering to control superradiance and subradiance in quantum emitters.

Findings

Controllable superradiance and subradiance achieved.

Real-time abrupt changes in emission rates demonstrated.

Potential implementation with superconducting circuits proposed.

Abstract

As one of the central topics in quantum optics, collective spontaneous emission such as superradiance has been realized in a variety of systems. This work proposes an innovative scheme to coherently control collective emission rates via a self-interference mechanism in a nonlinear waveguide setting. The self-interference is made possible by photon backward scattering incurred by quantum scatterers in a waveguide working as quantum switches. Whether the interference is constructive or destructive is found to depend strongly on the distance between the scatterers and the emitters. The interference between two propagation pathways of the same photon leads to controllable superradiance and subradiance, with their collective decay rates much enhanced or suppressed (also leading to hyperradiance or population trapping). Furthermore, the self-interference mechanism is manifested by an abrupt change in the emission rates in real time. An experimental setup based on superconducting transmission line resonators and transmon qubits is further proposed to realize controllable collective emission rates.