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REVIEW 4 major objections 5 minor 92 references

Quantum Teleportation from Telecom Photons to Erbium-ion Ensembles

T0 review · 4 major / 5 minor · reviewed 2026-08-15 · deepseek-v4-flash

Pith's one-line read A telecom photonic qubit is teleported into an erbium-ion ensemble memory, with state and process fidelities above classical thresholds.

desk verdict First teleportation into an erbium ensemble memory, but the quantum certification currently rests on an all-optical decoy analysis rather than the memory data. read the letter →

arxiv 2505.05233 v3 pith:OPWD5LG5 submitted 2025-05-08 quant-ph

classification quant-ph MSC 81P4581P68 PACS 03.67.Hk42.50.Ex
keywords quantumteleportationerbium-ionensemblememoryatomicfrequencycombtelecomC-bandtime-binqubitsiliconnitridemicroringdecoy-statemethod
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

The paper reports the teleportation of a time-bin quantum state carried by a telecom-wavelength photon into an ensemble of 167Er3+ ions doped into a Y2SiO5 crystal, where it is stored for about 2.2 microseconds and then read out. The entangled photon pair needed for teleportation is generated on a silicon-nitride microring chip, and the Bell-state measurement is done by two-photon interference on a fiber beam splitter. The measured average state fidelity is 0.818 ± 0.019 and the process fidelity is 0.736 ± 0.022, both reported to exceed the relevant classical limits; after applying the decoy-state method to the weak-coherent input, the single-photon fidelity lower bound is quoted as 81.82 ± 1.25%, more than 12 standard deviations above 2/3. If correct, this extends light-to-matter teleportation to a memory material with a native telecom C-band transition, which matters because it removes the need for wavelength conversion in fiber-based quantum networks.

What carries the argument

The load-bearing objects are time-bin qubits, a silicon-nitride dual-interferometer microring resonator source that emits narrowband (about 185 MHz) time-bin entangled photon pairs at telecom wavelengths, a fiber beam-splitter Bell-state analyzer that projects onto |Ψ−⟩, and an atomic-frequency-comb (AFC) memory in 167Er3+:Y2SiO5. The AFC, a spectral comb of absorption peaks, stores the signal photon for 2187 ns and re-emits it as an echo, mapping Alice's input state onto the retrieved photon. Certification is carried out by quantum state tomography, which reconstructs the density matrix, and quantum process tomography, which reconstructs the process matrix against the ideal σy process, with the decoy-state method used to extract a single-photon fidelity bound from weak-coherent statistics.

What would settle it

Recalculate the single-photon fidelity lower bound with the denominator of Eq. (S1.47) corrected from Y(0)_Lower to Y(1)_Lower, using the standard decoy-state expression $F^1_{\rm Lower} = 1 - E^1_{\rm Upper}$, and verify whether the decoy gains and error rates were recorded with the atomic-frequency-comb memory in the optical path; if the corrected $F^1_{\rm Lower}$ falls at or below 2/3, or the decoy data come from an all-optical setup without the memory, the reported more-than-12-standard-deviations certification collapses.

Watch

Extended reading notes

Core claim

The central claim is that a photonic qubit in the telecom C-band can be teleported into a solid-state erbium-ion ensemble memory with fidelity that cannot be explained classically. Alice's input qubit, a weak-coherent time-bin state, is interfered with the idler photon of a time-bin entangled pair on a beam splitter; the |Ψ−⟩ Bell-state outcome projects the signal photon into minus the Pauli-Y rotated input state, which then enters an atomic-frequency-comb memory prepared in 167Er3+:Y2SiO5 and is retrieved after 2187 ns. Quantum state tomography over the four input states |e⟩, |l⟩, |+⟩, and |+i⟩ gives an average fidelity of 0.818 ± 0.019, and process tomography gives a process fidelity of 0.736 ± 0.022. Because the input is a coherent state rather than a perfect single photon, the authors use the decoy-state method to bound the fidelity of the single-photon component, reporting a lower bound that clears the 2/3 classical threshold.

Load-bearing premise

The result depends on the statistical correction that converts results from faint laser pulses into an estimate for true single photons, and on that estimate being computed correctly from data that actually passed through the erbium memory; if the correction or the dataset is wrong, the margin over the classical limit loses support.

Editorial extensions

If this is right

  • An erbium-based solid-state quantum memory can serve as the receiving node for telecom photonic teleportation, allowing quantum-network nodes to operate directly in the fiber low-loss band.
  • Because all three photons in the experiment are at telecom wavelengths, the scheme can in principle be split across standard optical fiber between Alice and Bob without wavelength conversion.
  • The decoy-state-certified single-photon fidelity above 2/3 establishes the nonclassical character of the transfer even though the input was an attenuated laser pulse.
  • With spin-wave AFC storage, the same platform would gain on-demand readout and much longer memory times, which the authors argue raises heralded entanglement distribution rates in quantum repeaters.
  • The measured storage efficiency of roughly 1.1%, compared with the higher efficiency of an earlier praseodymium-based teleportation, identifies the efficiency gap that cavity-enhanced AFC is expected to close.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • A natural next check is to repeat the teleportation with a heralded single-photon input, which would make the comparison with the 2/3 classical bound direct instead of routed through decoy-state estimation.
  • The frequency-stabilization architecture, which locks three lasers to one reference cavity, solves a practical synchronization problem for chip-source-to-memory interfaces and could transfer to other narrowband sources and memories.
  • If the corrected decoy formula were to shift the single-photon fidelity below 2/3, the central certification would fail, but the underlying memory and source demonstrations would remain useful as a chip-to-crystal interface.
  • A concrete extension would be to insert a length of fiber between Alice's beam splitter and the memory and measure how teleportation fidelity degrades with distance, a step toward a real repeater node.
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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

4 major / 5 minor

Summary. This manuscript reports an experiment claiming quantum teleportation of a time-bin qubit encoded in a weak coherent telecom-wavelength photon into a 167Er3+:Y2SiO5 atomic-frequency-comb quantum memory. The authors generate narrow-band time-bin entangled photon pairs from a silicon-nitride microring, perform a Bell-state measurement on the idler and input photons, store the signal photon in the erbium ensemble, and retrieve it for quantum state tomography. They report an average state fidelity of 0.818±0.019 and a process fidelity of 0.736±0.022, with claims that these exceed classical limits, and use a decoy-state method to claim a single-photon teleportation fidelity lower bound of 81.82±1.25%. The supplementary notes contain the frequency stabilization, HOM interference model, quantum memory characterization, classical bound calculation, and decoy-state analysis.

Significance. If properly certified, this would be a notable advance: the first quantum teleportation of a photonic qubit into an erbium-based telecom-band solid-state memory, combining an integrated SiN photon-pair source with a rare-earth AFC memory. The experiment is technically demanding: three lasers are frequency-locked over a 600-GHz span, the source is characterized via frequency-resolved HOM interference, and the retrieved states are measured by QST/QPT with Monte Carlo uncertainties. The direct fidelity measurements are not derived from a model, and the manuscript includes explicit efficiency and error analyses. However, the certification that the memory-inclusive teleportation is quantum is currently not established by the statistics as presented.

major comments (4)
  1. [Main text, 'Quantum Teleportation Results'; Note S11, Eq. (S1.39)] The measured average fidelity 0.818±0.019 is claimed to be 'more than seven standard deviations above the classical bound of 2/3', but the input is a weak coherent state with mean photon number μ=0.0825. For such an input the coherent-state classical bound is 0.812 (Note S11), so the memory-inclusive data exceed that bound by only 0.3σ. This is the central certification step for teleportation into the erbium memory; comparing to 2/3 is not justified for weak coherent inputs, and the claim as written is unsupported.
  2. [Main text, DSM paragraph; Note S12] The decoy-state single-photon lower bound F1_Lower = 81.82±1.25% (stated as exceeding 2/3 by more than 12σ) is explicitly said to be 'based on all-optical setup'. The main text uses this bound to certify the teleportation system, but the central claim of the paper is teleportation into and out of the 167Er3+ memory. If Table S1/S2 data were collected without the quantum memory, the DSM analysis does not certify the memory-inclusive teleportation; the authors must either confirm that the DSM data include the memory or redo the certification with memory-inclusive data.
  3. [Eq. (S1.47), Note S12] The upper bound on the single-photon error rate E(1) is written with Y(0)_Lower in the denominator, but the derivation requires Y(1)_Lower (the lower bound on the single-photon yield) in the denominator after subtracting the vacuum contribution. As written, the formula is dimensionally and algebraically incorrect, and the 12σ margin must be recomputed once the typo is fixed.
  4. [Main text, QPT paragraph] The process fidelity 0.736±0.022 is compared with the maximum process fidelity of 0.5 for a classical strategy, but no classical bound for process fidelity under weak coherent inputs is derived. For the state fidelity the coherent-state bound is already 0.812 (Note S11), and an analogous bound for the process fidelity should be established before claiming that the process exceeds the classical limit. Without this, the process-fidelity comparison is not a valid certification.
minor comments (5)
  1. [Note S12, Eq. (S1.44)] The sentence 'The gain and quantum bit error rate are given by' ends with '[ ? ]' and the citation is missing; please add the reference.
  2. [Fig. 2 caption] The third panel is labeled '(c)' twice; the panel for Δ = 0.511 GHz should be '(d)'.
  3. [Main text, 'Input State Preparation'] 'Adjacent pluses' should read 'adjacent pulses'.
  4. [Note S11] The relation between the 'old' and 'new' photon-pair source data should be stated explicitly in the main text; Table 1 reports the memory-inclusive fidelities, whereas Table S1 reports all-optical fidelities with the improved source, and the reader should not have to infer which dataset is being referenced.
  5. [Note S1, Eq. (S1.4)] The sign of the |Ψ−⟩ term in the expansion differs from the subsequently stated projected state; please check the expansion or add a sentence explaining the sign convention.

Circularity Check

0 steps flagged · score 0.0 of 10

No circular derivation chain: teleportation fidelities are direct tomography measurements, and the classical and single-photon bounds are external benchmarks evaluated at measured parameters.

full rationale

The central result is an experimental state fidelity F = 0.818 ± 0.019 and process fidelity 0.736 ± 0.022 obtained by QST/QPT of retrieved photons after teleportation into the 167Er3+ AFC memory; these quantities come from measured coincidence counts, not from a fitted model whose output is then relabeled as a prediction. The classical limit quoted in the main text (2/3) is the standard single-photon bound, while Note S11 separately evaluates the weak-coherent-state bound F_class = 0.812 from Eq. (S1.39) at the measured mu_input = 0.0825; the mismatch between these benchmarks is a consistency issue in the comparison, not a circular reduction. The decoy-state lower bound F1_Lower is computed from measured gains and QBERs using the standard decoy-state estimator, Eqs. (S1.44)-(S1.49); although the decoy-state references include a coauthor, the estimator is externally established and does not assume the target fidelity. No fitted parameter is renamed as a prediction, no definition embeds the target quantity, and no load-bearing premise rests solely on the authors' own prior claims. The reliance of Table S1/Note S12 on the all-optical setup, the apparent Y(0)_Lower/Y(1)_Lower typo in Eq. (S1.47), and the unresolved '[ ? ]' citation marker in Note S12 are validity and editorial concerns about what exactly the DSM certifies, but they are not examples of a derivation reducing to its own inputs by construction.

Assumptions & free parameters 3 free parameters · 4 assumptions · 0 invented entities

The central claim depends on treating a weak coherent pulse as a qubit for tomography, on the Franson-type entanglement generated by SFWM being maximally entangled, and on the decoy-state method providing a valid lower bound on single-photon fidelity. The mean photon numbers are experimental settings chosen to maximize fidelity, and they set the value of the classical benchmark.

free parameters (3)
  • Input mean photon number μ_input = 0.0825
    Set as a trade-off between counting rate and fidelity; directly sets the coherent-state classical bound of 0.812 used in Note S11.
  • Idler mean photon number μ_idler = 0.019
    Set by on-chip pump power of 1.48 mW; higher pump increases multiphoton errors.
  • Decoy-state mean photon numbers ν1, ν2 = 0.0495, 0.0165
    Chosen for DSM estimation of single-photon fidelity in Note S12.
assumptions (4)
  • domain assumption The weak coherent state with μ=0.0825 can be treated as a qubit after post-selection for the purpose of quantum state and process tomography.
    Used throughout QST/QPT; multiphoton components are handled by DSM instead of by direct single-photon heralding.
  • domain assumption The Franson-type time-bin entangled state from SFWM in the SiN microring is a maximally entangled state |Φ+>.
    Eq. (S1.1); no entanglement witness beyond HOM visibility presented.
  • domain assumption The two-detector BSM on a beam splitter projects onto |Ψ-> with the identification of one early and one late click.
    Note S1; partial BSM efficiency 1/4 assumed.
  • standard math Standard linear optics and AFC quantum memory formalism.
    Background theory for the memory and the teleportation protocol.

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Pith. "Pith review of Quantum Teleportation from Telecom Photons to Erbium-ion Ensembles." pith.science (2026). https://pith.science/paper/OPWD5LG5

@misc{pith2026250505233,
  author       = {Pith},
  title        = {Pith review of: Quantum Teleportation from Telecom Photons to Erbium-ion Ensembles},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/OPWD5LG5}},
  note         = {Machine review of arXiv:2505.05233}
}
abstract

To realize a quantum internet, the distribution of quantum states via quantum teleportation with quantum memories is a key ingredient. Being compatible with existing fiber networks, entangled photons and quantum memories at telecom-wavelength are of central interest for such a scalable quantum network. Here, we demonstrate quantum teleportation from a telecom-wavelength photonic qubit to a solid-state quantum memory based on erbium-ion ensembles, which have a native optical transition at 1.5 $\mu$m telecom C-band. To accomplish this, we use chip-scale silicon nitride micro-resonators to generate entangled photons with narrow linewidth, compatible with the quantum memory. We confirm the quality of the quantum teleportation procedure using quantum state and process tomography techniques, in which both the quantum state and process fidelities exceeds the classical limit. These results pave the way for the realization of scalable quantum networks based on solid-state devices.

Figures

Figures reproduced from arXiv: 2505.05233 by the authors.

Figure 1
Figure 1. FIG. 1. Schematics of the experiment setup. (a) Frequency distribution and fine-tuning module facilitates frequency and [PITH_FULL_IMAGE:figures/full_fig_p003_1.png] view at source ↗
Figure 2
Figure 2. FIG. 2. Hong-Ou-Mandel interference in the frequency do [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. FIG. 3. Quantum process tomography of quantum telepor [PITH_FULL_IMAGE:figures/full_fig_p005_3.png] view at source ↗

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Works this paper leans on

92 extracted references · 61 canonical work pages

  1. [1]

    C. H. Bennett, G. Brassard, C. Cr´ epeau, R. Jozsa, A. Peres, and W. K. Wootters, Teleporting an unknown quantum state via dual classical and einstein-podolsky-rosen channels, Phys. Rev. Lett. 70, 1895 (1993)

  2. [2]

    c” for “coherent

    To characterize the fidelity of the state of signal photons after teleportation, Bob prepares an asymmetric Mach-Zehnder interferometer (AMZI) as the time-bin qubit analyzer. The two output ports of Bob’s AMZI correspond to projections onto the states|ψ±⟩ = 1√ 2(|e⟩±eiθ|l⟩). Hence, the probability of three-fold coincidence counts in the two output ports c...

  3. [3]

    Bouwmeester, J.-W

    D. Bouwmeester, J.-W. Pan, K. Mattle, M. Eibl, H. Weinfurter, and A. Zeilinger, Experimental quantum teleportation, Nature 390, 575 (1997)

  4. [4]

    Boschi, S

    D. Boschi, S. Branca, F. De Martini, L. Hardy, and S. Popescu, Experimental realization of teleporting an unknown pure quantum state via dual classical and einstein-podolsky-rosen channels, Phys. Rev. Lett. 80, 1121 (1998)

  5. [5]

    Furusawa, J

    A. Furusawa, J. L. Sørensen, S. L. Braunstein, C. A. Fuchs, H. J. Kimble, and E. S. Polzik, Unconditional quantum teleportation, Science 282, 706 (1998)

  6. [6]

    H. J. Kimble, The quantum internet, Nature 453, 1023 (2008)

  7. [7]

    Wehner, D

    S. Wehner, D. Elkouss, and R. Hanson, Quantum internet: A vision for the road ahead, Science 362, eaam9288 (2018)

  8. [8]

    M. D. Barrett, J. Chiaverini, T. Schaetz, J. Britton, W. M. Itano, J. D. Jost, E. Knill, C. Langer, D. Leibfried, R. Ozeri, and D. J. Wineland, Deterministic quantum teleportation of atomic qubits, Nature 429, 737 (2004)

Show all 92 references
  1. [9]

    Riebe, H

    M. Riebe, H. H¨ affner, C. F. Roos, W. H¨ ansel, J. Benhelm, G. P. T. Lancaster, T. W. K¨ orber, C. Becher, F. Schmidt-Kaler, D. F. V. James, and R. Blatt, Deterministic quantum teleportation with atoms, Nature 429, 734 (2004)

  2. [10]

    J. F. Sherson, H. Krauter, R. K. Olsson, B. Julsgaard, K. Hammerer, I. Cirac, and E. S. Polzik, Quantum teleportation between light and matter, Nature 443, 557 (2006)

  3. [11]

    Krauter, D

    H. Krauter, D. Salart, C. A. Muschik, J. M. Petersen, H. Shen, T. Fernholz, and E. S. Polzik, Deterministic quantum teleportation between distant atomic objects, Nature Physics 9, 400 (2013)

  4. [12]

    Y.-A. Chen, S. Chen, Z.-S. Yuan, B. Zhao, C.-S. Chuu, J. Schmiedmayer, and J.-W. Pan, Memory-built-in quantum teleportation with photonic and atomic qubits, Nature Physics 4, 103 (2008). 22

  5. [13]

    Bao, X.-F

    X.-H. Bao, X.-F. Xu, C.-M. Li, Z.-S. Yuan, C.-Y. Lu, and J.-W. Pan, Quantum teleportation between remote atomic- ensemble quantum memories, Proceedings of the National Academy of Sciences 109, 20347 (2012)

  6. [14]

    Olmschenk, D

    S. Olmschenk, D. N. Matsukevich, P. Maunz, D. Hayes, L.-M. Duan, and C. Monroe, Quantum teleportation between distant matter qubits, Science 323, 486 (2009)

  7. [15]

    N¨ olleke, A

    C. N¨ olleke, A. Neuzner, A. Reiserer, C. Hahn, G. Rempe, and S. Ritter, Efficient teleportation between remote single-atom quantum memories, Phys. Rev. Lett. 110, 140403 (2013)

  8. [16]

    W. Gao, P. Fallahi, E. Togan, A. Delteil, Y. Chin, J. Miguel-Sanchez, and A. Imamo˘ glu, Quantum teleportation from a propagating photon to a solid-state spin qubit, Nature Communications 4, 2744 (2013)

  9. [17]

    Fiaschi, B

    N. Fiaschi, B. Hensen, A. Wallucks, R. Benevides, J. Li, T. P. M. Alegre, and S. Gr¨ oblacher, Optomechanical quantum teleportation, Nature Photonics 15, 817 (2021)

  10. [18]

    Afzelius, C

    M. Afzelius, C. Simon, H. de Riedmatten, and N. Gisin, Multimode quantum memory based on atomic frequency combs, Phys. Rev. A 79, 052329 (2009)

  11. [19]

    J. V. Rakonjac, D. Lago-Rivera, A. Seri, M. Mazzera, S. Grandi, and H. de Riedmatten, Entanglement between a telecom photon and an on-demand multimode solid-state quantum memory, Phys. Rev. Lett. 127, 210502 (2021)

  12. [20]

    Businger, L

    M. Businger, L. Nicolas, T. S. Mejia, A. Ferrier, P. Goldner, and M. Afzelius, Non-classical correlations over 1250 modes between telecom photons and 979-nm photons stored in 171Yb3+:Y2SiO5, Nature Communications 13, 6438 (2022)

  13. [21]

    S.-H. Wei, B. Jing, X.-Y. Zhang, J.-Y. Liao, H. Li, L.-X. You, Z. Wang, Y. Wang, G.-W. Deng, H.-Z. Song, D. Oblak, G.-C. Guo, and Q. Zhou, Quantum storage of 1650 modes of single photons at telecom wavelength, npj Quantum Information 10, 19 (2024)

  14. [22]

    Zhong, M

    M. Zhong, M. P. Hedges, R. L. Ahlefeldt, J. G. Bartholomew, S. E. Beavan, S. M. Wittig, J. J. Longdell, and M. J. Sellars, Optically addressable nuclear spins in a solid with a six-hour coherence time, Nature 517, 177 (2015)

  15. [23]

    Ma, Y.-Z

    Y. Ma, Y.-Z. Ma, Z.-Q. Zhou, C.-F. Li, and G.-C. Guo, One-hour coherent optical storage in an atomic frequency comb memory, Nature Communications 12, 2381 (2021)

  16. [24]

    M. P. Hedges, J. J. Longdell, Y. Li, and M. J. Sellars, Efficient quantum memory for light, Nature 465, 1052 (2010)

  17. [25]

    Duranti, S

    S. Duranti, S. Wengerowsky, L. Feldmann, A. Seri, B. Casabone, and H. de Riedmatten, Efficient cavity-assisted storage of photonic qubits in a solid-state quantum memory, Optics Express 32, 26884 (2024)

  18. [26]

    Bussi` eres, C

    F. Bussi` eres, C. Clausen, A. Tiranov, B. Korzh, V. B. Verma, S. W. Nam, F. Marsili, A. Ferrier, P. Goldner, H. Herrmann, C. Silberhorn, W. Sohler, M. Afzelius, and N. Gisin, Quantum teleportation from a telecom-wavelength photon to a solid-state quantum memory, Nature Photon...

  19. [27]

    Lago-Rivera, J

    D. Lago-Rivera, J. V. Rakonjac, S. Grandi, and H. d. Riedmatten, Long distance multiplexed quantum teleportation from a telecom photon to a solid-state qubit, Nature Communications 14, 1889 (2023)

  20. [28]

    Liu, X.-M

    X. Liu, X.-M. Hu, T.-X. Zhu, C. Zhang, Y.-X. Xiao, J.-L. Miao, Z.-W. Ou, P.-Y. Li, B.-H. Liu, Z.-Q. Zhou, C.-F. Li, and G.-C. Guo, Nonlocal photonic quantum gates over 7.0 km, Nature Communications 15, 8529 (2024)

  21. [29]

    Lauritzen, J

    B. Lauritzen, J. c. v. Min´ aˇ r, H. de Riedmatten, M. Afzelius, N. Sangouard, C. Simon, and N. Gisin, Telecommunication- wavelength solid-state memory at the single photon level, Phys. Rev. Lett. 104, 080502 (2010)

  22. [30]

    A. M. Dibos, M. Raha, C. M. Phenicie, and J. D. Thompson, Atomic source of single photons in the telecom band, Phys. Rev. Lett. 120, 243601 (2018)

  23. [31]

    Merkel, A

    B. Merkel, A. Ulanowski, and A. Reiserer, Coherent and purcell-enhanced emission from erbium dopants in a cryogenic high-q resonator, Phys. Rev. X 10, 041025 (2020)

  24. [32]

    Huang, P.-J

    J.-Y. Huang, P.-J. Liang, L. Zheng, P.-Y. Li, Y.-Z. Ma, D.-C. Liu, J.-H. Xie, Z.-Q. Zhou, C.-F. Li, and G.-C. Guo, Stark tuning of telecom single-photon emitters based on a single Er 3+, Chinese Physics Letters 40, 070301 (2023)

  25. [33]

    Ourari, L

    S. Ourari, L. Dusanowski, S. P. Horvath, M. T. Uysal, C. M. Phenicie, P. Stevenson, M. Raha, S. Chen, R. J. Cava, N. P. De Leon, and J. D. Thompson, Indistinguishable telecom band photons from a single Er ion in the solid state, Nature 620, 977 (2023)

  26. [34]

    Y. Yu, D. Oser, G. Da Prato, E. Urbinati, J. C. ´Avila, Y. Zhang, P. Remy, S. Marzban, S. Gr¨ oblacher, and W. Tittel, Frequency tunable, cavity-enhanced single erbium quantum emitter in the telecom band, Phys. Rev. Lett. 131, 170801 (2023)

  27. [35]

    Gritsch, A

    A. Gritsch, A. Ulanowski, J. Pforr, and A. Reiserer, Optical single-shot readout of spin qubits in silicon (2024), arXiv:2405.05351 [quant-ph]

  28. [36]

    M. T. Uysal, Lukasz Dusanowski, H. Xu, S. P. Horvath, S. Ourari, R. J. Cava, N. P. de Leon, and J. D. Thompson, Spin-photon entanglement of a single Er 3+ ion in the telecom band (2024), arXiv:2406.06515 [quant-ph]

  29. [37]

    Ranˇ ci´ c, M

    M. Ranˇ ci´ c, M. P. Hedges, R. L. Ahlefeldt, and M. J. Sellars, Coherence time of over a second in a telecom-compatible quantum memory storage material, Nature Physics 14, 50 (2018)

  30. [38]

    Craiciu, M

    I. Craiciu, M. Lei, J. Rochman, J. M. Kindem, J. G. Bartholomew, E. Miyazono, T. Zhong, N. Sinclair, and A. Faraon, Nanophotonic quantum storage at telecommunication wavelength, Phys. Rev. Appl. 12, 024062 (2019)

  31. [39]

    J. S. Stuart, M. Hedges, R. Ahlefeldt, and M. Sellars, Initialization protocol for efficient quantum memories using resolved hyperfine structure, Phys. Rev. Res. 3, L032054 (2021)

  32. [40]

    Liu, P.-Y

    D.-C. Liu, P.-Y. Li, T.-X. Zhu, L. Zheng, J.-Y. Huang, Z.-Q. Zhou, C.-F. Li, and G.-C. Guo, On-demand storage of photonic qubits at telecom wavelengths, Phys. Rev. Lett. 129, 210501 (2022)

  33. [41]

    Jiang, W

    M.-H. Jiang, W. Xue, Q. He, Y.-Y. An, X. Zheng, W.-J. Xu, Y.-B. Xie, Y. Lu, S. Zhu, and X.-S. Ma, Quantum storage of entangled photons at telecom wavelengths in a crystal, Nature Communications 14, 6995 (2023)

  34. [42]

    Weinfurter, Experimental Bell-state analysis, Europhysics Letters 25, 559 (1994)

    H. Weinfurter, Experimental Bell-state analysis, Europhysics Letters 25, 559 (1994)

  35. [43]

    D. F. V. James, P. G. Kwiat, W. J. Munro, and A. G. White, Measurement of qubits, Phys. Rev. A 64, 052312 (2001). 23

  36. [44]

    M. A. Nielsen and I. L. Chuang, Quantum Computation and Quantum Information: 10th Anniversary Edition (Cambridge University Press, 2010)

  37. [45]

    See supplemental material at [url] for theoretical and experimental details, which includes [1, 42, 66–70, 74–76, 79–83, 90, 91]

  38. [46]

    J. D. Franson, Bell inequality for position and time, Phys. Rev. Lett. 62, 2205 (1989)

  39. [47]

    Reimer, L

    C. Reimer, L. Caspani, M. Clerici, M. Ferrera, M. Kues, M. Peccianti, A. Pasquazi, L. Razzari, B. E. Little, S. T. Chu, D. J. Moss, and R. Morandotti, Integrated frequency comb source of heralded single photons, Opt. Express22, 6535 (2014)

  40. [48]

    Mazeas, M

    F. Mazeas, M. Traetta, M. Bentivegna, F. Kaiser, D. Aktas, W. Zhang, C. A. Ramos, L. A. Ngah, T. Lunghi, E. Picholle, N. Belabas-Plougonven, X. L. Roux, E. Cassan, D. Marris-Morini, L. Vivien, G. Sauder, L. Labont´ e, and S. Tanzilli, High- quality photonic entanglement for wa...

  41. [49]

    J. A. Jaramillo-Villegas, P. Imany, O. D. Odele, D. E. Leaird, Z.-Y. Ou, M. Qi, and A. M. Weiner, Persistent energy-time entanglement covering multiple resonances of an on-chip biphoton frequency comb, Optica 4, 655 (2017)

  42. [50]

    Samara, A

    F. Samara, A. Martin, C. Autebert, M. Karpov, T. J. Kippenberg, H. Zbinden, and R. Thew, High-rate photon pairs and sequential time-bin entanglement with Si 3N4 microring resonators, Opt. Express 27, 19309 (2019)

  43. [51]

    Zeng, Z.-Q

    H. Zeng, Z.-Q. He, Y.-R. Fan, Y. Luo, C. Lyu, J.-P. Wu, Y.-B. Li, S. Liu, D. Wang, D.-C. Zhang, J.-J. Zeng, G.-W. Deng, Y. Wang, H.-Z. Song, Z. Wang, L.-X. You, K. Guo, C.-Z. Sun, Y. Luo, G.-C. Guo, and Q. Zhou, Quantum light generation based on GaN microring toward fully on-c...

  44. [52]

    X. Li, P. L. Voss, J. E. Sharping, and P. Kumar, Optical-fiber source of polarization-entangled photons in the 1550 nm telecom band, Phys. Rev. Lett. 94, 053601 (2005)

  45. [53]

    Ramelow, A

    S. Ramelow, A. Farsi, S. Clemmen, D. Orquiza, K. Luke, M. Lipson, and A. L. Gaeta, Silicon-nitride platform for narrow- band entangled photon generation (2015), arXiv:1508.04358 [quant-ph]

  46. [54]

    Samara, N

    F. Samara, N. Maring, A. Martin, A. S. Raja, T. J. Kippenberg, H. Zbinden, and R. Thew, Entanglement swapping between independent and asynchronous integrated photon-pair sources, Quantum Science and Technology 6, 045024 (2021)

  47. [55]

    Y.-R. Fan, C. Lyu, C.-Z. Yuan, G.-W. Deng, Z.-Y. Zhou, Y. Geng, H.-Z. Song, Y. Wang, Y.-F. Zhang, R.-B. Jin, H. Zhou, L.-X. You, Z. Wang, G.-C. Guo, and Q. Zhou, Multi-wavelength quantum light sources on silicon nitride micro-ring chip, Laser & Photonics Reviews 17, 2300172 (2023)

  48. [56]

    Chen, Y.-H

    R. Chen, Y.-H. Luo, J. Long, B. Shi, C. Shen, and J. Liu, Ultralow-loss integrated photonics enables bright, narrowband, photon-pair sources, Phys. Rev. Lett. 133, 083803 (2024)

  49. [57]

    W. Wen, Z. Chen, L. Lu, W. Yan, W. Xue, P. Zhang, Y. Lu, S. Zhu, and X.-s. Ma, Realizing an entanglement-based multiuser quantum network with integrated photonics, Phys. Rev. Appl. 18, 024059 (2022)

  50. [58]

    M. Kues, C. Reimer, J. M. Lukens, W. J. Munro, A. M. Weiner, D. J. Moss, and R. Morandotti, Quantum optical microcombs, Nature Photonics 13, 170 (2019)

  51. [59]

    X. Lu, Q. Li, D. A. Westly, G. Moille, A. Singh, V. Anant, and K. Srinivasan, Chip-integrated visible–telecom entangled photon pair source for quantum communication, Nature Physics 15, 373 (2019)

  52. [60]

    W. Wen, W. Yan, C. Lu, L. Lu, X. Wu, Y. Lu, S. Zhu, and X.-S. Ma, Polarization-entangled quantum frequency comb from a silicon nitride microring resonator, Phys. Rev. Appl. 20, 064032 (2023)

  53. [61]

    Vernon, M

    Z. Vernon, M. Menotti, C. C. Tison, J. A. Steidle, M. L. Fanto, P. M. Thomas, S. F. Preble, A. M. Smith, P. M. Alsing, M. Liscidini, and J. E. Sipe, Truly unentangled photon pairs without spectral filtering, Opt. Lett. 42, 3638 (2017)

  54. [62]

    C. C. Tison, J. A. Steidle, M. L. Fanto, Z. Wang, N. A. Mogent, A. Rizzo, S. F. Preble, and P. M. Alsing, Path to increasing the coincidence efficiency of integrated resonant photon sources, Opt. Express 25, 33088 (2017)

  55. [63]

    L. Lu, L. Xia, Z. Chen, L. Chen, T. Yu, T. Tao, W. Ma, Y. Pan, X. Cai, Y. Lu, S. Zhu, and X.-S. Ma, Three-dimensional entanglement on a silicon chip, npj Quantum Information 6, 30 (2020)

  56. [64]

    C. Wu, Y. Liu, X. Gu, X. Yu, Y. Kong, Y. Wang, X. Qiang, J. Wu, Z. Zhu, X. Yang, and P. Xu, Bright photon-pair source based on a silicon dual-Mach-Zehnder microring, Science China Physics, Mechanics & Astronomy 63, 10.1007/s11433-019- 1429-1 (2019)

  57. [65]

    L. Chen, L. Lu, L. Xia, Y. Lu, S. Zhu, and X.-s. Ma, On-chip generation and collectively coherent control of the superposition of the whole family of Dicke states, Phys. Rev. Lett. 130, 223601 (2023)

  58. [66]

    C. K. Hong, Z. Y. Ou, and L. Mandel, Measurement of subpicosecond time intervals between two photons by interference, Phys. Rev. Lett. 59, 2044 (1987)

  59. [67]

    L. Duan, A. Xu, and Y. Zhang, Spectral characterization of two-photon interference between independent sources, Photonics 10 (2023)

  60. [68]

    Valivarthi, M

    R. Valivarthi, M. G. Puigibert, Q. Zhou, G. H. Aguilar, V. B. Verma, F. Marsili, M. D. Shaw, S. W. Nam, D. Oblak, and W. Tittel, Quantum teleportation across a metropolitan fibre network, Nature Photonics 10, 676 (2016)

  61. [69]

    Z. Y. Ou and L. Mandel, Observation of spatial quantum beating with separated photodetectors, Phys. Rev. Lett. 61, 54 (1988)

  62. [70]

    J. G. Rarity and P. R. Tapster, Two-color photons and nonlocality in fourth-order interference, Phys. Rev. A 41, 5139 (1990)

  63. [71]

    Legero, T

    T. Legero, T. Wilk, A. Kuhn, and G. Rempe, Time-resolved two-photon quantum interference, Applied Physics B 77, 797 (2003)

  64. [72]

    B¨ ottger, Y

    T. B¨ ottger, Y. Sun, C. W. Thiel, and R. L. Cone, Spectroscopy and dynamics of Er 3+ : Y2SiO5 at 1.5µm, Phys. Rev. B 74, 075107 (2006)

  65. [73]

    Altepeter, E

    J. Altepeter, E. Jeffrey, and P. Kwiat, Photonic state tomography (Academic Press, 2005) pp. 105–159

  66. [74]

    Takesue, S

    H. Takesue, S. D. Dyer, M. J. Stevens, V. Verma, R. P. Mirin, and S. W. Nam, Quantum teleportation over 100 km of 24 fiber using highly efficient superconducting nanowire single-photon detectors, Optica 2, 832 (2015)

  67. [75]

    Massar and S

    S. Massar and S. Popescu, Optimal extraction of information from finite quantum ensembles, Phys. Rev. Lett. 74, 1259 (1995)

  68. [76]

    H.-K. Lo, X. Ma, and K. Chen, Decoy state quantum key distribution, Phys. Rev. Lett. 94, 230504 (2005)

  69. [77]

    X. Ma, B. Qi, Y. Zhao, and H.-K. Lo, Practical decoy state for quantum key distribution, Phys. Rev. A 72, 012326 (2005)

  70. [78]

    J.-P. Li, X. Gu, J. Qin, D. Wu, X. You, H. Wang, C. Schneider, S. H¨ ofling, Y.-H. Huo, C.-Y. Lu, N.-L. Liu, L. Li, and J.-W. Pan, Heralded nondestructive quantum entangling gate with single-photon sources, Phys. Rev. Lett. 126, 140501 (2021)

  71. [79]

    G.-S. Ye, B. Xu, Y. Chang, S. Shi, T. Shi, and L. Li, A photonic entanglement filter with Rydberg atoms, Nature Photonics 17, 538 (2023)

  72. [80]

    Sinclair, E

    N. Sinclair, E. Saglamyurek, H. Mallahzadeh, J. A. Slater, M. George, R. Ricken, M. P. Hedges, D. Oblak, C. Simon, W. Sohler, and W. Tittel, Spectral multiplexing for scalable quantum photonics using an atomic frequency comb quantum memory and feed-forward control, Phys. Rev. ...

  73. [81]

    Lago-Rivera, S

    D. Lago-Rivera, S. Grandi, J. V. Rakonjac, A. Seri, and H. de Riedmatten, Telecom-heralded entanglement between multimode solid-state quantum memories, Nature 594, 37 (2021)

  74. [82]

    H¨ anni, A

    J. H¨ anni, A. E. Rodr´ ıguez-Moldes, F. Appas, S. Wengerowsky, D. Lago-Rivera, M. Teller, S. Grandi, and H. de Riedmatten, Heralded entanglement of on-demand spin-wave solid-state quantum memories for multiplexed quantum network links (2025), arXiv:2501.04131 [quant-ph]

  75. [83]

    Simon, H

    C. Simon, H. de Riedmatten, M. Afzelius, N. Sangouard, H. Zbinden, and N. Gisin, Quantum repeaters with photon pair sources and multimode memories, Phys. Rev. Lett. 98, 190503 (2007)

  76. [84]

    Sangouard, C

    N. Sangouard, C. Simon, H. de Riedmatten, and N. Gisin, Quantum repeaters based on atomic ensembles and linear optics, Rev. Mod. Phys. 83, 33 (2011)

  77. [85]

    A. Ortu, A. Tiranov, S. Welinski, F. Fr¨ owis, N. Gisin, A. Ferrier, P. Goldner, and M. Afzelius, Simultaneous coherence enhancement of optical and microwave transitions in solid-state electronic spins, Nature Materials 17, 671 (2018)

  78. [86]

    Businger, A

    M. Businger, A. Tiranov, K. T. Kaczmarek, S. Welinski, Z. Zhang, A. Ferrier, P. Goldner, and M. Afzelius, Optical spin-wave storage in a solid-state hybridized electron-nuclear spin ensemble, Phys. Rev. Lett. 124, 053606 (2020)

  79. [87]

    Sabooni, S

    M. Sabooni, S. T. Kometa, A. Thuresson, S. Kr¨ oll, and L. Rippe, Cavity-enhanced storage-preparing for high-efficiency quantum memories, New Journal of Physics 15, 035025 (2013)

  80. [88]

    Sabooni, Q

    M. Sabooni, Q. Li, S. Kr¨ oll, and L. Rippe, Efficient quantum memory using a weakly absorbing sample, Phys. Rev. Lett. 110, 133604 (2013)

  81. [89]

    Jobez, I

    P. Jobez, I. Usmani, N. Timoney, C. Laplane, N. Gisin, and M. Afzelius, Cavity-enhanced storage in an optical spin-wave memory, New Journal of Physics 16, 083005 (2014)

  82. [90]

    J. H. Davidson, P. Lefebvre, J. Zhang, D. Oblak, and W. Tittel, Improved light-matter interaction for storage of quantum states of light in a thulium-doped crystal cavity, Phys. Rev. A 101, 042333 (2020)

  83. [91]

    G¨ undo˘ gan, P

    M. G¨ undo˘ gan, P. M. Ledingham, A. Almasi, M. Cristiani, and H. de Riedmatten, Quantum storage of a photonic polar- ization qubit in a solid, Phys. Rev. Lett. 108, 190504 (2012)

  84. [92]

    H. P. Specht, C. N¨ olleke, A. Reiserer, M. Uphoff, E. Figueroa, S. Ritter, and G. Rempe, A single-atom quantum memory, Nature 473, 190 (2011)

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