Microcavity controlled coupling of excitonic qubits

TL;DR

This paper demonstrates controlled coherent coupling of spatially separated excitonic qubits via a microresonator photon mode, advancing quantum information processing and light harvesting technologies.

Contribution

It provides experimental evidence and theoretical modeling of cavity-mediated coupling of excitonic qubits in solid state systems, a novel approach for non-local quantum interactions.

Findings

Successful demonstration of photon-mediated coupling between excitonic qubits

Quantitative agreement between experiment and cavity coupling theory

Potential for scalable, long-range quantum networks in solids

Abstract

Controlled non-local energy and coherence transfer enables light harvesting in photosynthesis and non-local logical operations in quantum computing. The most relevant mechanism of coherent coupling of distant qubits is coupling via the electromagnetic field. Here, we demonstrate the controlled coherent coupling of spatially separated excitonic qubits via the photon mode of a solid state microresonator. This is revealed by two-dimensional spectroscopy of the sample's coherent response, a sensitive and selective probe of the coherent coupling. The experimental results are quantitatively described by a rigorous theory of the cavity mediated coupling within a cluster of quantum dots excitons. Having demonstrated this mechanism, it can be used in extended coupling channels - sculptured, for instance, in photonic crystal cavities - to enable a long-range, non-local wiring up of individual emitters in solids.