Proposal for room-temperature quantum repeaters with nitrogen-vacancy centers and optomechanics

Abstract

We propose a quantum repeater architecture that can operate under ambient conditions. Our proposal builds on recent progress towards non-cryogenic spin-photon interfaces based on nitrogenvacancy centers, which have excellent spin coherence times even at room temperature, and optomechanics, which allows to avoid phonon-related decoherence and also allows the emitted photons to be in the telecom band. We apply the photon number decomposition method to quantify the fidelity and the efficiency of entanglement established between two remote electron spins. We describe how the entanglement can be stored in nuclear spins and extended to long distances via quasi-deterministic entanglement swapping operations involving the electron and nuclear spins. We furthermore propose schemes to achieve high-fidelity readout of the spin states at room temperature using the spin-optomechanics interface. Our work shows that long-distance quantum networks made of solid-state components that operate at room temperature are within reach of current technological capabilities.

A spin-optomechanical quantum interface enabled by an ultrasmall mechanical and optical mode volume cavity

“…This entanglement procedure completely circumvents standard issues related to spin-addressing, including the need to operate at the emitter's optical transition wavelength (we define the optical wavelength with a telecom photonic mode) and concerns related to spectral diffusion of emitters (we never optically excite the emitter). Additionally, this scheme places no strong requirements on the optical quality factors required by other works to accomplish spinmechanical addressing [51,52]-instead operating with low optical Qs to increase the rate of heralding-and re-FIG. 7.…”