Control design for inhomogeneous broadening compensation in single-photon transducers

TL;DR

This paper presents a gradient-based optimization method to design laser pulse shapes that mitigate inhomogeneous broadening effects in single-photon transducers, enhancing quantum communication between distant superconducting computers.

Contribution

It introduces a novel pulse shaping strategy to counteract inhomogeneous broadening in quantum emitter ensembles for improved transduction efficiency.

Findings

Optimized laser pulses improve transduction efficiency under broadening.

Restoration of superradiance effects correlates with efficiency gains.

Certifiable bounds validate the optimality of the pulse designs.

Abstract

A transducer of single photons between microwave and optical frequencies can be used to realize quantum communication over optical fiber links between distant superconducting quantum computers. A promising scalable approach to constructing such a transducer is to use ensembles of quantum emitters interacting simultaneously with electromagnetic fields at optical and microwave frequencies. However, inhomogeneous broadening in the transition frequencies of the emitters can be detrimental to this collective action. In this article, we utilise a gradient-based optimization strategy to design the temporal shape of the laser field driving the transduction system to mitigate the effects of inhomogeneous broadening. We study the improvement of transduction efficiencies as a function of inhomogeneous broadening in different single-emitter cooperativity regimes and correlate it with a restoration of superradiance effects in the emitter ensembles. Furthermore, to assess the optimality of our pulse designs, we provide certifiable bounds on the design problem and compare them to the achieved performance.