High fidelity transfer and storage of photon states in a single nuclear spin

TL;DR

This paper demonstrates a high-fidelity transfer and long-term storage of photon states in a single nuclear spin within a diamond nitrogen vacancy center, advancing quantum communication and computing capabilities.

Contribution

It introduces a method for coherently transferring photon states to a nuclear spin with 98% fidelity and storing them for over 10 seconds in a solid-state system.

Findings

Photon-to-nuclear spin transfer fidelity of 98%

Storage duration exceeds 10 seconds

Robust against optical writing operations

Abstract

Building a quantum repeater network for long distance quantum communication requires photons and quantum registers that comprise qubits for interaction with light, good memory capabilities and processing qubits for storage and manipulation of photons. Here we demonstrate a key step, the coherent transfer of a photon in a single solid-state nuclear spin qubit with an average fidelity of 98% and storage over 10 seconds. The storage process is achieved by coherently transferring a photon to an entangled electron-nuclear spin state of a nitrogen vacancy centre in diamond, confirmed by heralding through high fidelity single-shot readout of the electronic spin states. Stored photon states are robust against repetitive optical writing operations, required for repeater nodes. The photon-electron spin interface and the nuclear spin memory demonstrated here constitutes a major step towards practical quantum networks, and surprisingly also paves the way towards a novel entangled photon source for photonic quantum computing.