Quantum repeaters based on individual electron spins and nuclear-spin-ensemble memories in quantum dots

TL;DR

This paper proposes a quantum repeater scheme using quantum dots with electron spins and nuclear-spin ensembles for long-distance entanglement, leveraging recent advances in quantum dot control.

Contribution

It introduces a novel quantum repeater design combining electron spins and nuclear-spin ensembles in quantum dots for improved entanglement distribution.

Findings

Enables long-term storage of entangled states in nuclear-spin ensembles.

Uses cavity-assisted gates for heralded entanglement swapping.

Promises higher entanglement distribution rates than direct photon transmission.

Abstract

Inspired by recent developments in the control and manipulation of quantum dot nuclear spins, which allow for the transfer of an electron spin state to the surrounding nuclear-spin ensemble for storage, we propose a quantum repeater scheme that combines individual quantum dot electron spins and nuclear-spin ensembles, which serve as spin-photon interfaces and quantum memories respectively. We consider the use of low-strain quantum dots embedded in high-cooperativity optical microcavities. Quantum dot nuclear-spin ensembles allow for the long-term storage of entangled states, and heralded entanglement swapping is performed using cavity-assisted gates. We highlight the advances in quantum dot technologies required to realize our quantum repeater scheme which promises the establishment of high-fidelity entanglement over long distances with a distribution rate exceeding that of the direct transmission of photons.