The DOI matches its Crossref record; 72 of the 77 references it cites were found in a registry or an index; 13 of the 24 sources its claims cite were checked for support.
Entanglement of Trapped-Ion Qubits Separated by 230 Meters
Open accessAbstract
We report on an elementary quantum network of two atomic ions separated by 230 m. The ions are trapped in different buildings and connected with 520(2) m of optical fiber. At each network node, the electronic state of an ion is entangled with the polarization state of a single cavity photon; subsequent to interference of the photons at a beam splitter, photon detection heralds entanglement between the two ions. Fidelities of up to (88.0+2.2-4.7)% are achieved with respect to a maximally entangled Bell state, with a success probability of 4×10^{-5}. We analyze the routes to improve these metrics, paving the way for long-distance networks of entangled quantum processors.
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TL;DR
Two trapped-ion nodes in separate buildings 230 m apart were entangled using cavity-generated photons sent through 520(2) m of optical fiber and interfered at a beam splitter. Bell-state fidelities reached up to about 88% for short coincidence windows, with a correspondingly low heralding success probability.
Key findings
- The experiment entangled two single \(^{40}\mathrm{Ca}^+\) ions in different buildings separated by 230 m, connected by 520(2) m of fiber, with entanglement heralded by coincident detection of two 854 nm photons after beam-splitter interference.
- For a coincidence window \(T=1\,\mu\mathrm{s}\), the reconstructed Bell-state fidelities were \(F_+ = (88.0^{+2.2}_{-4.7})\%\) and \(F_- = (83.3^{+3.3}_{-6.4})\%\), based on 555 coincidence events and a rate of 3.5 min\(^{-1}\). For \(T=17.5\,\mu\mathrm{s}\), fidelities fell to \(F_+ = (58.7^{+1.7}_{-2.1})\%\) and \(F_- = (58.0^{+2.0}_{-2.9})\%\).
- Across 13,656,928 attempts, 4470 coincidences were recorded in the 5.5–23 \(\mu\mathrm{s}\) interval, giving a 0.033% success probability per attempt and a 0.49 s\(^{-1}\) entanglement rate; the high-fidelity \(T=1\,\mu\mathrm{s}\) subset corresponds to roughly \(4\times10^{-5}\) success probability.
- Calibration measurements gave ion-photon entanglement fidelities of \((92.9^{+0.4}_{-0.5})\%\) at Node A and \((95.5^{+0.6}_{-0.9})\%\) at Node B, while two-photon interference visibility reached 101(6)% for \(T=0.25\,\mu\mathrm{s}\). Fidelity decreased with longer coincidence windows, which the models attribute to reduced photon indistinguishability, detector background, imperfect ion-photon entanglement, and technical noise.
Methods
- Each node used a single \(^{40}\mathrm{Ca}^+\) ion in a linear Paul trap coupled to a 20 mm cavity; a bichromatic cavity-mediated Raman transition generated an ion-photon entangled state, and photons from the two nodes were overlapped on a balanced beam splitter for a photonic Bell-state measurement.
- Data were acquired over seven hours, with up to 20 attempts per entanglement sequence, 0.3 ms initialization, a 50 \(\mu\mathrm{s}\) Raman pulse, and a 50 \(\mu\mathrm{s}\) detection window; the ion-ion state was reconstructed by quantum state tomography over nine Pauli basis combinations using maximum-likelihood estimation, with uncertainties from Monte Carlo resampling.
- Two models were used: an empirical two-qubit density-matrix model incorporating photon distinguishability via Hong-Ou-Mandel visibility, detector background, and imperfect ion-photon entanglement; and a master-equation model for visibility including cavity frequency jitter, Raman-laser phase noise, and spontaneous emission.
Limitations
- The paper has no dedicated limitations section. It states that fidelity and heralding efficiency trade off: longer coincidence windows lower fidelity because photon distinguishability increases, and spontaneous emission is identified as the most significant challenge. Technical noise from cavity jitter (60–100 kHz) and Raman-laser phase noise, plus temporal wave-packet mismatch, also limit visibility.
- Evident from the text: only one ion per node was used, so register-based processing at network nodes was not demonstrated; the high-fidelity regime has a very low success probability, and the reported rates are 0.49 s\(^{-1}\) for the broader window and 3.5 min\(^{-1}\) for \(T=1\,\mu\mathrm{s}\).
- The phase \(\phi\) was optimized from the data rather than determined independently from the node phases \(\theta_A\) and \(\theta_B\), which is an evident methodological limitation for full independent characterization.
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15 Own result · 7 Sources not found · 7 Own interpretation · 4 Supported · 4 No basis given · 3 Partly supported · 2 Own method · 1 Couldn’t confirm · accuracy not yet measured
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“The remote ion-ion state is characterized via quantum state tomography, for which the sequence is repeated for all nine combinations of the Pauli measurement bases for 2 ion qubits [52].”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
What the sources say
- Partly supportedcites [52] 52. D. F. V. James, P. G. Kwiat, W. J. Munro, and A. G. White, Measurement of qubits, Phys. Rev. A 64, 052312 (2001). sourceExperimental — accuracy not yet measured
Section B, “Multiple beam Stokes parameters: multiple qubit tomography” (p. 4), supports tomography of two-qubit states and relates its measurement operators to Pauli operators. It describes a set of 16 measurements, however, not a sequence repeated for nine combinations of Pauli bases. The Introduction (p. 2) says its experiments use photon-polarization qubits, so it does not document the remote ion-ion procedure. (LLM, conf=0.85)
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The cited sources that could be checked couldn’t confirm or dispute this claim.
In the paper
“The probability for dephasing in the channel is parametrized by the Hong-Ou-Mandel (HOM) interference visibility, which provides direct information about photon indistinguishability [58].”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
What the sources say
- Could not verifycites [58] 58. G. Vittorini, D. Hucul, I. V. Inlek, C. Crocker, and C. Monroe, Entanglement of distinguishable quantum memo- ries, Phys. Rev. A 90, 040302(R) (2014). sourceExperimental — accuracy not yet measured
The discussion on p. 1 links photon distinguishability and detection timing to decoherence, and p. 3 discusses fidelity loss from time-dependent phase shifts. Neither passage parametrizes a channel’s dephasing probability by Hong–Ou–Mandel interference visibility. Searches for HOM visibility and interference visibility found no passage establishing that relationship. (LLM, conf=0.72)
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In the paper
“It is notable that the success probabilities shown in Fig. 2(b) are comparable to those achieved over a few meters in Ref. [10]”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
What the sources say
- Supportedcites [10] 10. L. J. Stephenson, D. P. Nadlinger, B. C. Nichol, S. An, P. Drmota, T. G. Ballance, K. Thirumalai, J. F. Goodwin, D. M. Lucas, and C. J. Ballance, High-Rate, High-Fidelity Entanglement of Qubits Across an Elementary Quantum Network, Phys. Rev. Lett. 124, 110501 (2020). source
The main text (p. 2) says the two ion-trap systems were separated by 2 m. The Fig. S3 caption in S3. ION-ION TOMOGRAPHY (p. 8) reports an entanglement-heralding success probability of 2.18 × 10⁻⁴ per attempt. The cited paper therefore supplies a success probability achieved over a few metres; the citing document’s Fig. 2(b) is not part of this source. (LLM, conf=0.88)
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In the paper
“Furthermore, efficient, low-noise and entanglement-preserving telecom wavelength conversion of the 854 nm photons used in the present Letter has been achieved [25,26]”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
What the sources say
- Supportedcites [25] 25. M. Bock, P. Eich, S. Kucera, M. Kreis, A. Lenhard, C. Becher, and J. Eschner, High-fidelity entanglement between a trapped ion and a telecom photon via quantum frequency conversion, Nat. Commun. 9, 1998 (2018). source
The Abstract reports polarization-preserving conversion of 854 nm photons to the 1310 nm telecom band, with 26.5% external efficiency and an 11.4 photons/s conversion-induced background. It also reports 98.2 ± 0.2% fidelity for entanglement between a trapped ion and the converted telecom photon. (LLM, conf=0.94)
- Supportedcites [26] 26. V. Krutyanskiy, M. Meraner, J. Schupp, V. Krcmarsky, H. Hainzer, and B. P. Lanyon, Light-matter entanglement over 50 km of optical fibre, npj Quantum Inf. 5, 72 (2019). source
The Introduction (p. 2) reports conversion of 854 nm photons to 1550 nm with 25% device efficiency and 40 added noise photons per second. The Introduction (p. 3) reports an entangled-state fidelity of 0.92 ± 0.02 after conversion, supporting the entanglement-preserving description. (LLM, conf=0.93)
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“At each network node, the electronic state of an ion is entangled with the polarization state of a single cavity photon”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
plaincorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“We report on an elementary quantum network of two atomic ions separated by 230 m.”
- Also stated in: § Abstract · plain
“In this Letter, we report on the entanglement of two trapped ions separated by 230 m.”
- Also stated in: § Abstract · boosted
“we have verified entanglement over the longest trapped-ion network to date”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
boostedcorrelational- Asserted: passes — The authors put it forward as true.
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- Rests on an assumption: Remote entanglement of trapped ions more than a few meters apart had not previously been reported.
- Also stated in: § Abstract · plain
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“subsequent to interference of the photons at a beam splitter, photon detection heralds entanglement between the two ions.”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“The HOM dip at τ ¼ 0 can be clearly observed.”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
boosted- Asserted: passes — The authors put it forward as true.
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In the paper
“resulting in 4470 coincidence events within the interval ½t ¼ 5.5 μs; t ¼ 23 μs [Fig.2(a)], corresponding to a 0.033% probability of two-photon coincidence per attempt, which we define as the success probability.”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“resulting in 4470 coincidence events within the interval ½t ¼ 5.5 μs; t ¼ 23 μs [Fig.2(a)]”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
plain- Asserted: passes — The authors put it forward as true.
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- It may state two separate claims as one. 12
- Probably not a substantial claim. 8
Every source the paper cites for this claim was checked and supports it.
In the paper
“our photon generation method is based on a cavity-mediated Raman process providing tunable entangled states [34] and high efficiency [35], which are advantageous for establishing long-distance entanglement [36].”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
What the sources say
- Supportedcites [34] 34. A. Stute, B. Casabone, P. Schindler, T. Monz, P. O. Schmidt, B. Brandstätter, T. E. Northup, and R. Blatt, Tunable ion- photon entanglement in an optical cavity, Nature (London) 485, 482 (2012). source
Citation [34] is attached to the tunable-entangled-states portion of the sentence, not the high-efficiency or long-distance claims assigned to [35] and [36]. The Abstract states that the paper's bichromatic, cavity-mediated Raman method allows control of the relative phase and amplitude of an ion–photon entangled state. (LLM, conf=0.94)
- Supportedcites [35] 35. J. Schupp, V. Krcmarsky, V. Krutyanskiy, M. Meraner, T. Northup, and B. Lanyon, Interface between trapped-ion qubits and traveling photons with close-to-optimal effi- ciency, PRX Quantum 2, 020331 (2021). source
The citation to this paper is attached to “high efficiency,” rather than to tunable entangled states or long-distance entanglement. Section IV (p. 5) reports a 0.69(3) probability of collecting an ion-entangled photon at the cavity output, and the Conclusion (p. 8) describes the collection efficiency as a significant advance. (LLM, conf=0.94)
- Supportedcites [36] 36. N. Sangouard, R. Dubessy, and C. Simon, Quantum repeaters based on single trapped ions, Phys. Rev. A 79, 042340 (2009). source
The citation to this paper is attached to the advantage for establishing long-distance entanglement, not specifically to tunable states or high efficiency. The paper’s opening summary (p. 1) describes cavity-emitted photons used to entangle remote ions and successive swapping to extend entanglement over long distances; the Introduction (p. 1) also identifies efficient photon collection as a requirement of the protocol. (LLM, conf=0.91)
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In the paper
“a particular strength of the trapped-ion platform is the capability for quantuminformation processing with dozens of addressed qubits in a single trap [22,23] and fidelities sufficient for faulttolerant gate operations and error correction [62,63].”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
What the sources say
- Partly supportedcites [22] 22. C. D. Bruzewicz, J. Chiaverini, R. McConnell, and J. M. Sage, Trapped-ion quantum computing: Progress and chal- lenges, Appl. Phys. Rev. 6, 021314 (2019). sourceExperimental — accuracy not yet measured
The introduction (p. 2) says trapped-ion gates, preparation, and readout have achieved fidelities above those required by high-threshold fault-tolerant error-correction codes. But the DiVincenzo Criteria section (p. 3) reports only 20 ions in the largest fully controlled register, while Pros and Cons (p. 4) says larger chains with meaningful control and readout had not demonstrated entanglement between arbitrary ions. The copy therefore does not establish quantum-information processing with dozens of individually addressed qubits in one trap. (LLM, conf=0.86)
- Supportedcites [23] 23. N. Friis, O. Marty, C. Maier, C. Hempel, M. Holzäpfel, P. Jurcevic, M. B. Plenio, M. Huber, C. Roos, R. Blatt, and B. Lanyon, Observation of Entangled States of a Fully Controlled 20-Qubit System, Phys. Rev. X 8, 021012 (2018). source
The Abstract reports 20 individually controlled trapped-ion qubits, and the Introduction states that each can be individually manipulated and read out. The Experimental Setup describes the ions in a single linear Paul trap. The separate claim about fault-tolerant fidelities is attached to citations [62,63], not this source. (LLM, conf=0.91)
- Not checked — no full text of the sourcecites [62] 62. P. Kobel, M. Breyer, and M. Köhl, Deterministic spin- photon entanglement from a trapped ion in a fiber Fabry- Perot cavity, npj Quantum Inf. 7, 6 (2021). source
- Not checked — no full text of the sourcecites [63] 63. C. Ryan-Anderson, J. G. Bohnet, K. Lee, D. Gresh, A. Hankin, J. P. Gaebler, D. Francois, A. Chernoguzov, D. Lucchetti, N. C. Brown, T. M. Gatterman, S. K. Halit, K. Gilmore, J. A. Gerber, B. Neyenhuis, D. Hayes, and R. P. Stutz, Realization of Real-Time Fault-Tolerant Quantum Error Correction, Phys. Rev. X 11, 041058 (2021). source
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Probably not a substantial claim. It may state two separate claims as one.
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The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“This capability provides a route to robust logical qubit encodings at network nodes [64], separate communication and information processing functionalities within each node [5,21], and quantum repeaters requiring Bell state measurements and either purification or error correction [65].”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
What the sources say
- Partly supportedcites [64] 64. L. Postler, S. Heußen, I. Pogorelov, M. Rispler, T. Feldker, M. Meth, C. D. Marciniak, R. Stricker, M. Ringbauer, R. Blatt, P. Schindler, M. Müller, and T. Monz, Demonstration of fault-tolerant universal quantum gate operations, Nature (London) 605, 675 (2022). sourceExperimental — accuracy not yet measured
Split into 3 atoms — 0 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 2 unverifiable. Expand the claim to see per-atom verdicts.
- Partly supportedcites [5] 5. C. Monroe, R. Raussendorf, A. Ruthven, K. R. Brown, P. Maunz, L.-M. Duan, and J. Kim, Large-scale modular quantum-computer architecture with atomic memory and photonic interconnects, Phys. Rev. A 89, 022317 (2014). sourceExperimental — accuracy not yet measured
Split into 3 atoms — 2 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.
- Not checked — no full text of the sourcecites [21] 21. L.-M. Duan and C. Monroe, Colloquium: Quantum networks with trapped ions, Rev. Mod. Phys. 82, 1209 (2010). source
- Not checked — no full text of the sourcecites [65] 65. M. Zwerger, B. P. Lanyon, T. E. Northup, C. A. Muschik, W. Dür, and N. Sangouard, Quantum repeaters based on trapped ions with decoherence-free subspace encoding, Quantum Sci. Technol. 2, 044001 (2017). source
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Every source the paper cites for this claim was checked and supports it.
In the paper
“in future long-distance networks limited by photon travel time, it will be success probabilities that determine entanglement rates [36].”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
What the sources say
- Supportedcites [36] 36. N. Sangouard, R. Dubessy, and C. Simon, Quantum repeaters based on single trapped ions, Phys. Rev. A 79, 042340 (2009). source
In Section II (p. 2), the paper gives the probability of a successful entanglement-creation attempt and states that attempts are spaced by the photon communication time L₀/c. It uses these quantities to calculate the average time to create entanglement, supporting the claim that success probability determines the rate when attempts are limited by photon travel time. (LLM, conf=0.88)
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Probably not a substantial claim. The paper’s conclusions may not depend on it.
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A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Fidelities of up to ð88.0 þ 2.2 -4.7Þ% are achieved with respect to a maximally entangled Bell state, with a success probability of 4 × 10 -5 .”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
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In the paper
“In total, 13 656 928 attempts were made to generate remote entanglement”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
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In the paper
“We optimize F Æ over the phase ϕ in Eq. ( 1) because we did not determine θ A and θ B independently; this optimization yields ϕ ¼ 82.2°.”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“The fidelities of the reconstructed states are F þ ð17.5 μsÞ ¼ ð58.7 þ 1.7 -2.1Þ% and F -ð17.5 μsÞ ¼ ð58.0þ2.0-2.9Þ%”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
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In the paper
“The fidelities of the reconstructed states are F þ ð1 μsÞ ¼ ð88.0 þ 2.2 -4.7Þ% and F -ð1 μsÞ ¼ ð83.3 þ 3.3 -6.4Þ%.”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“The density matrices shown in Fig. 2(c) correspond to T ¼ 1 μs, for which we recorded 555 coincidence events, that is, a remote entanglement rate of 3.5 min -1 .”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
plaincorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“Ion-photon entanglement was characterized in a calibration measurement at each node via quantum state tomography immediately prior to ion-ion entanglement, and fidelities of ð92.9 þ 0.4 -0.5Þ% and ð95.5 þ 0.6 -0.9Þ% with respect to a maximally entangled state were obtained at Nodes A and B, respectively.”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
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In the paper
“A detailed model is developed that captures the observed trade-off between the fidelity of remote entanglement and the heralding efficiency and shows how significant improvements can be made in the future.”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
plaincorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“The solid lines are calculated from the full model, taking into account all three sources of infidelity, while the dashed lines are calculated when photon distinguishability is excluded from the model.”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
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Probably not a substantial claim.
- The authors state this as an assumption: For ion-photon entanglement, imperfections translate as a 2-qubit depolarizing channel on the ion-ion state.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Spectral indistinguishability of the photons requires matching the resonant frequencies of the remote cavities.This is achieved via periodic calibration at 20 min intervals: 854 nm laser light that is resonant with the cavity at Node A is sent to Node B over a third fiber in the bundle, and the length of the Node B cavity is adjusted until it is resonant with this light.”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“For example, spontaneous emission during the Raman process provides information on which ion generated which cavity photon [53][54][55], that is, scattering introduces which-path information.”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
What the sources say
- Not matchedcites [53][54][55]
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Not matched
In the paper
“All parameter values used in the model are statistically consistent with independent estimates and determined via comparison of the model to measured single-photon wave packets (see the Supplemental Material [40]).”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
What the sources say
- Not matchedcites [40] 40. See Supplemental Material at http://link.aps.org/ supplemental/10.1103/PhysRevLett.130.050803 for details on the synchronization and stabilization procedures between the two nodes, a full description of our density-matrix model, an independent characterization of the noise sources, and the calculation of interference visibility, including Refs. [41-51].
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- The authors state this as an assumption: For ion-photon entanglement, imperfections translate as a 2-qubit depolarizing channel on the ion-ion state.
- Not matched
In the paper
“Uncertainties for F Æ ðTÞ and for all quantities derived from the density matrices are obtained via Monte Carlo resampling (see the Supplemental Material [40]).”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
What the sources say
- Not matchedcites [40] 40. See Supplemental Material at http://link.aps.org/ supplemental/10.1103/PhysRevLett.130.050803 for details on the synchronization and stabilization procedures between the two nodes, a full description of our density-matrix model, an independent characterization of the noise sources, and the calculation of interference visibility, including Refs. [41-51].
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim.
- Not matched
In the paper
“Also at 20 min intervals, the polarization rotation of the fiber that carries single photons is characterized and corrected for (see the Supplemental Material [40]).”
§ Entanglement of Trapped-Ion Qubits Separated by 230 Meters > Abstract
What the sources say
- Not matchedcites [40] 40. See Supplemental Material at http://link.aps.org/ supplemental/10.1103/PhysRevLett.130.050803 for details on the synchronization and stabilization procedures between the two nodes, a full description of our density-matrix model, an independent characterization of the noise sources, and the calculation of interference visibility, including Refs. [41-51].
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim.
- Not matched
The paper relies on this without support.
Remote entanglement of trapped ions more than a few meters apart had not previously been reported.
“Remote entanglement of trapped ions more than a few meters apart has not previously been reported.”
The authors state this as an assumption.
For ion-photon entanglement, imperfections translate as a 2-qubit depolarizing channel on the ion-ion state.
“For ion-photon entanglement, we assume that imperfections translate as a 2-qubit depolarizing channel on the ionion state (see the Supplemental Material [40]).”
Citations
Cites
An Introduction to the Bootstrap
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Kimble, H. J. (2008) · Nature · doi:10.1038/nature07127 · Cited by 6,023
Measurement of subpicosecond time intervals between two photons by interference
Hong, C. K., Ou, Z. Y., & Mandel, L. (1987) · Physical Review Letters · doi:10.1103/physrevlett.59.2044 · Cited by 4,369
Loophole-free Bell inequality violation using electron spins separated by 1.3 kilometres
Hensen, B., Bernien, H., Dréau, A. E., Reiserer, A., Kalb, N., Blok, M. S., Ruitenberg, J., Vermeulen, R. F. L., Schouten, R. N., Abellán, C., et al. (2015) · Nature · doi:10.1038/nature15759 · Cited by 2,852
Quantum internet: a vision for the road ahead
Wehner, S., Elkouss, D., & Hanson, R. (2018) · Science · doi:10.1126/science.aam9288 · Cited by 2,467
James, D. F. V., Kwiat, P. G., Munro, W. J., & White, A. G. (2001) · Physical Review A · doi:10.1103/physreva.64.052312 · Cited by 2,176 · cited 2×
“trapped neutral atoms [11, 12], color centers in dia-”
BackgroundMethodAdvances in quantum cryptography
Pirandola, S., Andersen, U. L., Banchi, L., Berta, M., Bunandar, D., Colbeck, R., Englund, D., Gehring, T., Lupo, C., Ottaviani, C., et al. (2020) · Advances in Optics and Photonics · doi:10.1364/aop.361502 · Cited by 2,033
Advances in Quantum Cryptography
Pirandola, S., Andersen, U. L., Banchi, L., Berta, M., Bunandar, D., Colbeck, R., Englund, D., Gehring, T., Lupo, C., Ottaviani, C., et al. (2019) · White Rose Research Online (University of Leeds, The University of Sheffield, University of York) · Cited by 1,566
Trapped-ion quantum computing: Progress and challenges
Bruzewicz, C. D., Chiaverini, J., McConnell, R., & Sage, J. M. (2019) · Applied Physics Reviews · doi:10.1063/1.5088164 · Cited by 1,483
Heralded entanglement between solid-state qubits separated by three metres
Bernien, H., Hensen, B., Pfaff, W., Koolstra, G., Blok, M. S., Robledo, L., Taminiau, T. H., Markham, M., Twitchen, D. J., Childress, L., et al. (2013) · Nature · doi:10.1038/nature12016 · Cited by 1,187
Cited by
Sorted by citations
Entanglement of nanophotonic quantum memory nodes in a telecom network
Knaut, C. M., Suleymanzade, A., Wei, Y.-C., Assumpção, D., Stas, P.-J., Huan, Y. Q., Machielse, B., Knall, E., Sutula, M., Baranes, G., et al. (2024) · Nature · doi:10.1038/s41586-024-07252-z · Cited by 373
“By integrating efficient bidirectional quantum frequency conversion of photonic communication qubits to telecommunication frequencies (1,350 nm), we demonstrate the entanglement of two nuclear spin memories through 40 km spools of low-loss fibre and a 35-km long fibre loop deployed in the Boston…”
Progress in quantum teleportation
Hu, X., Guo, Y., Liu, B., Li, C., & Guo, G. (2023) · Nature Reviews Physics · doi:10.1038/s42254-023-00588-x · Cited by 293
Quantum networks with neutral atom processing nodes
Covey, J. P., Weinfurter, H., & Bernien, H. (2023) · npj Quantum Information · doi:10.1038/s41534-023-00759-9 · Cited by 142
Review of Distributed Quantum Computing: From single QPU to High Performance Quantum Computing
Barral, D., Cardama, F. J., Díaz-Camacho, G., Faílde, D., Llovo, I. F., Juane, M. M., Vázquez-Pérez, J., Villasuso, J., Piñeiro, C., Costas, N., et al. (2025) · Computer Science Review · doi:10.1016/j.cosrev.2025.100747 · Cited by 179
“After the subsequent BSM, fidelities to Bell states of up to 88% at 230 m have been demonstrated in trapped-ions [123], and deterministic qubit state transfer between different NV-center nodes has also been shown [78].”
Telecom-Wavelength Quantum Repeater Node Based on a Trapped-Ion Processor
Krutyanskiy, V. L., Canteri, M., Meraner, M., Bate, J., Krcmarsky, V., Schupp, J., Sangouard, N., & Lanyon, B. P. (2023) · Physical Review Letters · doi:10.1103/physrevlett.130.213601 · Cited by 125
“Two remote trapped ions have previously been entangled over a few meters [11,14,22,23] and, using the ion-cavity system of this work, over 230 m [24].”
BackgroundMethodSelf-citation
Metadata
- Authors
- Krutyanskiy, V., Galli, M., Krcmarsky, V., Baier, S., Fioretto, D. A., Pu, Y., Mazloom, A., Sekatski, P., Canteri, M., Teller, M., Schupp, J., Bate, J., Meraner, M., Sangouard, N., Lanyon, B. P., & Northup, T. E.
- Affiliations
- Austrian Academy of Sciences (AT)
- Universität Innsbruck (AT)
- Georgetown University (US)
- University of Geneva (CH)
- Centre National de la Recherche Scientifique (FR)
- Corresponding author
- Lanyon, B. P.
- ORCID
- Venue
- Physical Review Letters
- Publisher
- American Physical Society (APS)
- Published
- 2023-02-02
- Volume
- 130
- Issue
- 5
- Pages
- 050803-050803
- ISSN
- 0031-9007 (ISSN-L)
- 1079-7114
- OpenAlex
- W4294320751
- Cited by
- 217
- References
- 77
- Citations by year
- 2026: 46 · 2025: 85 · 2024: 54 · 2023: 32
- FWCI
- 20.49
- Type
- journal article
- Language
- en
- Open access
- green
- hal.science
- Licence
- Locations
- Physical Review Letters (publishedVersion)
- PubMed (publishedVersion)
- HAL (submittedVersion)
- arXiv (Cornell University) (submittedVersion)
- Digital Library of the University of Innsbruck (University of Innsbruck) (submittedVersion)
- arXiv (Cornell University)
- Funders
- Horizon 2020 Framework Programme (820445)
- Austrian Science Fund (F 7109, Y 849, J 4229)
- Army Research Office (W911NF-15-2-0060)
- National Science Foundation (PHY-1915130)
- Commissariat à l’Énergie Atomique et aux Énergies Alternatives
- Topics
- Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Quantum Information and Cryptography
- Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Quantum optics and atomic interactions
- Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Quantum Mechanics and Applications
- Keywords
- trapped-ion qubits, quantum networks, optical fiber links, cavity quantum electrodynamics, entanglement fidelity, quantum repeaters
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
A language model drew the claims from the paper on 2026-10-11, under version 3 of the claim definition (model deepseek-v4.1-flash, prompt extract-v3).
A second model labelled each claim on 2026-10-11 (model jev-1.13-20260917, definition revision gold-guideline-v0.2).
Cited sources are checked with a language model’s help (gpt-6-sol).
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
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