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Entangling remote qubits using the single-photon protocol: an in-depth theoretical and experimental study

Hermans, S. L. N. and Pompili, M. and Dos Santos Martins, L. and Montblanch, A. R-P. and Beukers, H. K. C. and Baier, S. and Borregaard, J. and Hanson, R. (2023) Entangling remote qubits using the single-photon protocol: an in-depth theoretical and experimental study. New Journal of Physics, 25 (1). Art. No. 013011. ISSN 1367-2630. doi:10.1088/1367-2630/acb004.

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The generation of entanglement between remote matter qubits has developed into a key capability for fundamental investigations as well as for emerging quantum technologies. In the single-photon, protocol entanglement is heralded by generation of qubit-photon entangled states and subsequent detection of a single photon behind a beam splitter. In this work we perform a detailed theoretical and experimental investigation of this protocol and its various sources of infidelity. We develop an extensive theoretical model and subsequently tailor it to our experimental setting, based on nitrogen-vacancy centers in diamond. Experimentally, we verify the model by generating remote states for varying phase and amplitudes of the initial qubit superposition states and varying optical phase difference of the photons arriving at the beam splitter. We show that a static frequency offset between the optical transitions of the qubits leads to an entangled state phase that depends on the photon detection time. We find that the implementation of a Charge-Resonance check on the nitrogen-vacancy center yields transform-limited linewidths. Moreover, we measure the probability of double optical excitation, a significant source of infidelity, as a function of the power of the excitation pulse. Finally, we find that imperfect optical excitation can lead to a detection-arm-dependent entangled state fidelity and rate. The conclusion presented here are not specific to the nitrogen-vacancy centers used to carry out the experiments, and are therefore readily applicable to other qubit platforms.

Item Type:Article
Related URLs:
URLURL TypeDescription
Hermans, S. L. N.0000-0002-1060-5199
Pompili, M.0000-0002-8360-1957
Dos Santos Martins, L.0000-0001-9775-4957
Beukers, H. K. C.0000-0001-9934-1099
Baier, S.0000-0002-2840-5590
Borregaard, J.0000-0003-2544-4073
Hanson, R.0000-0001-8938-2137
Additional Information:We acknowledge financial support from the EU Flagship on Quantum Technologies through the project Quantum Internet Alliance (EU Horizon 2020, Grant Agreement No. 820445); from the European Research Council (ERC) through an ERC Consolidator Grant (Grant Agreement No. 772627 to R H); from the Netherlands Organisation for Scientific Research (NWO) through a VICI Grant (Project No. 680-47-624) and the Zwaartekracht program Quantum Software Consortium (Project No. 024.003.037/3368). S B acknowledges support from an Erwin-Schrödinger fellowship (QuantNet, No. J 4229-N27) of the Austrian National Science Foundation (FWF).
Funding AgencyGrant Number
Foundation for Technical Sciences (STW)024.003.037/3368
European Research Council (ERC)772627
European Research Council (ERC)820445
FWF Der WissenschaftsfondsJ 4229-N27
Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)680-47-624
Issue or Number:1
Record Number:CaltechAUTHORS:20230203-893712500.45
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:119037
Deposited By: Research Services Depository
Deposited On:01 Mar 2023 01:33
Last Modified:01 Mar 2023 01:33

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