Two-photon interference: the Hong–Ou–Mandel effect

In the paper

“In the works mentioned above, a noncommon-path HOM interferometer is employed to measure time shifts with resolutions on the order of a few femto-seconds (micrometers), where the time shifts are obtained by assessing the shift of the HOM dip.”

What the sources say

• ?Could not verify

  The Introduction describes a HOM coincidence dip, but does not say it was used to measure time shifts. The Experimental Setup reports coincidence measurements and an 81-ps time-interval analyzer; a search for femtosecond resolution, noncommon-path time-shift measurement, and shifts of the HOM dip found no supporting passage in our copy. (LLM, conf=0.76)

  cites [16] Moschandreou, 2018, Experimental study of Hong–Ou–Mandel interference using independent phase randomized weak coherent states, J. Lightwave Technol. sourceExperimental — accuracy not yet measured
• Disputed

  The Results report that this paper’s time-resolved HOM interference is not affected by temporal delay between the input photons; adding optical delay lines did not shift or degrade the interference. Its reported detection-time bin is 0.5 ns, not a few femtoseconds. This experiment therefore does not measure input time shifts by tracking a HOM-dip shift as the citing sentence claims. (LLM, conf=0.83)

  Checked by a reasoning model — may be wrong.

  cites [17] Kim, 2020, Hong–Ou–Mandel interference of two independent continuous-wave coherent photons, Photon. Res. sourceExperimental — accuracy not yet measured
• Partly supported

  The Results and Discussions section reports scanning the relative pulse delay and recording a HOM dip, which supports the time-shift measurement aspect. It gives a dip width of 2.40 ns, but does not describe a noncommon-path HOM interferometer or report resolution of a few femtoseconds. (LLM, conf=0.85)

  cites [18] Ferreira da Silva, 2013, Proof-of-principle demonstration of measurement-device-independent quantum key distribution using polarization qubits, Phys. Rev. A sourceExperimental — accuracy not yet measured

In the paper

“The resulting probability of finding two indistinguishable atoms in one trap exceeded the probability for distinguishable atoms by 6 standard deviations”

What the sources say

• Disputed

  The section “Demonstrating genuinely quantum operation and circuit complexity” describes interference experiments with photons in an integrated circuit, not atoms in a trap. It reports that one measured visibility exceeded a classical limit by more than one standard deviation, not that a two-atom trap probability exceeded another by six standard deviations. (LLM, conf=0.87)

  Checked by a reasoning model — may be wrong.

  cites [190] Metcalf, 2013, Multiphoton quantum interference in a multiport integrated photonic device, Nat. Commun. sourceExperimental — accuracy not yet measured

In the paper

“Recently, this deficiency was resolved by an improved experiment, using two separate sources of single electrons emitted from a triggered quantum dot [197,198].”

What the sources say

• ?Not checked — no full text of the sourcecites [197] Spring, 2012, Boson sampling on a photonic chip, Science source
• Disputed

  The Experiment section (p. 2) says the input was generated by spontaneous parametric down-conversion, and Methods (pp. 4–5) describes photon pairs produced in a BBO crystal. The cited experiment used photons, not single electrons emitted from two triggered quantum-dot sources. (LLM, conf=0.90)

  Checked by a reasoning model — may be wrong.

  cites [198] Tillmann, 2013, Experimental boson sampling, Nat. Photon. sourceExperimental — accuracy not yet measured

In the paper

“bunching was confirmed through a dip with a visibility up to 0.89±0.06 in the correlation measurements of the two photons (see Fig. 8f) by varying the distinguishability and splitting ratio.”

What the sources say

• Disputed

  In Results, “Control of photon-pair propagation” (Fig. 4; page unavailable), the paper associates photon bunching with constructive interference and a peak, while the dip occurs under a destructive-interference phase setting. Our copy does not report a visibility of 0.89±0.06 or describe varying a splitting ratio for this result. (LLM, conf=0.86)

  Checked by a reasoning model — may be wrong.

  cites [182] Defienne, 2016, Two-photon quantum walk in a multimode fiber, Sci. Adv. sourceExperimental — accuracy not yet measured

In the paper

“Recently, such a two-phonon interference effect has been observed involving two trapped ions [181].”

What the sources say

• Disputed

  The Abstract (page unavailable) describes an experiment on two-photon interference in multimode optical waveguides, not two-phonon interference involving trapped ions. The experimental-system passage describes laser light and photon-pair generation, rather than an ion-trap experiment. (LLM, conf=0.90)

  Checked by a reasoning model — may be wrong.

  cites [181] Poem, 2012, Two-photon path-entangled states in multimode waveguides, Phys. Rev. Lett. sourceExperimental — accuracy not yet measured

In the paper

“two recent experiments, both using very different approaches, have shown exactly this: a two-atom HOM interference.”

What the sources say

• Disputed

  The paper describes Hong–Ou–Mandel-type interference with three input photons, not atoms (Abstract; page unavailable). Figure 3 also reports two-photon interference measurements. It therefore does not describe either of the claimed two-atom experiments. (LLM, conf=0.90)

  Checked by a reasoning model — may be wrong.

  cites [190] Metcalf, 2013, Multiphoton quantum interference in a multiport integrated photonic device, Nat. Commun. sourceExperimental — accuracy not yet measured
• Disputed

  In the section labeled Abstract (page unavailable), the paper describes Hong–Ou–Mandel interference among photons, including verified two-photon combinations, not two-atom interference. It describes its own high-dimensional teleportation experiment rather than reporting two experiments that demonstrate the claimed effect. (LLM, conf=0.88)

  Checked by a reasoning model — may be wrong.

  cites [192] Luo, 2019, Quantum teleportation in high dimensions, Phys. Rev. Lett. sourceExperimental — accuracy not yet measured

In the paper

“Several realizations of the RRDPS protocol have recently been demonstrated experimentally using time-bin phase encoding [103][104][105][106] and using transverse spatial modes [107].”

What the sources say

• ?Could not verify

  The copy’s section C, “Differential phase shift QKD,” describes experimental implementations of differential phase-shift QKD, but does not identify them as RRDPS. Searches for “RRDPS,” “round-robin differential phase shift,” and “transverse spatial modes” found no passage establishing the claimed RRDPS demonstrations. The copy is truncated, so relevant text may be missing. (LLM, conf=0.72)

  cites [103] Pirandola, 2019, Advances in quantum cryptography sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [104] Wootters, 1982, A single quantum cannot be cloned, Nature source
• ?Could not verify

  The Protocol 3: BB84 discussion (p. 4) concerns BB84 security and mentions experimental quantum key distribution systems only in general. Searches for RRDPS, time-bin phase encoding, transverse spatial modes, and experimental demonstrations found no passage addressing the claimed realizations. (LLM, conf=0.76)

  cites [105] Shor, 2000, Simple proof of security of the bb84 quantum key distribution protocol, Phys. Rev. Lett. sourceExperimental — accuracy not yet measured
• ?Could not verify

  The Abstract describes a proposed event-ready Bell experiment using entanglement swapping, not an experimental realization of RRDPS. Searches for RRDPS, time-bin phase encoding, and transverse spatial modes found no passage addressing the claimed demonstrations. (LLM, conf=0.78)

  cites [106] Zukowski, 1993, ‘Event-ready-detectors’ Bell experiment via entanglement swapping, Phys. Rev. Lett. sourceExperimental — accuracy not yet measured
• ?Could not verify

  The passages labeled Abstract discuss quantum teleportation using EPR pairs and classical communication, not experimental RRDPS implementations. Searches for RRDPS, time-bin phase encoding, and transverse spatial modes found no passage addressing the claim; page numbers are unavailable in our copy. (LLM, conf=0.78)

  cites [107] Bennett, 1993, Teleporting an unknown quantum state via dual classical and Einstein–Podolsky–Rosen channels, Phys. Rev. Lett. sourceExperimental — accuracy not yet measured

In the paper

“Optimal 1 → 2 cloning (i.e. two clones of one original state) of a qudit can be achieved with a fidelity of F cloning = 1 2 + 1 d+1 [114][115][116][117].”

What the sources say

• ?Could not verify

  Appendix F (page unavailable) discusses fidelity for a two-qubit entanglement experiment, not optimal qudit cloning. Searches for the cloning formula and for universal qudit cloning found no passage addressing the claimed fidelity. (LLM, conf=0.75)

  cites [114] Narla, 2016, Robust concurrent remote entanglement between two superconducting qubits, Phys. Rev. X sourceExperimental — accuracy not yet measured
• ?Could not verify

  The paper’s discussion of the no-cloning theorem (Abstract; page unavailable) concerns the impossibility of noiseless amplification, not the fidelity of optimal approximate cloning. Searches for qudit cloning and the formula 1/2 + 1/(d+1) found no passage in our copy addressing the claimed result. (LLM, conf=0.76)

  cites [115] Sangouard, 2011, Quantum repeaters based on atomic ensembles and linear optics, Rev. Mod. Phys. sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [116] Briegel, 1998, Quantum repeaters: the role of imperfect local operations in quantum communication, Phys. Rev. Lett. source
• ?Could not verify

  The paper’s section V discusses a phase-remapping intercept-and-resend attack, and Appendix A minimizes quantum bit error rate, not cloning fidelity. Searches for optimal 1→2 qudit cloning and the stated formula found no passage addressing either; the claim cannot be verified from our copy. (LLM, conf=0.74)

  cites [117] Fung, 2007, Phase-remapping attack in practical quantum-key-distribution systems, Phys. Rev. A sourceExperimental — accuracy not yet measured

In the paper

“In this scheme, the two-photon interference is exploited to achieve extremely large dimensions such as 10 5 .”

What the sources say

• Partly supported

  The paper reports two-photon interference through Hong–Ou–Mandel dips (pp. 2–3). It does not describe a passive RRDPS scheme or say that interference achieves dimensions of 10^5; its conclusion (p. 4) instead reports a 136-fold enhancement in entangled-photon-pair generation. (LLM, conf=0.84)

  cites [85] Yuan, 2007, Synchronized independent narrow-band single photons and efficient generation of photonic entanglement, Phys. Rev. Lett. sourceExperimental — accuracy not yet measured

In the paper

“Moreover, for the same bandwidth, QOCT benefits from an extra factor of 2 in resolution compared to classical OCT.”

What the sources say

• Partly supported

  Section 6, “Quantum Imaging and Sensing” (page not provided), reports a factor-of-two improvement in resolving power for quantum coherence tomography. It does not specify that the comparison with classical OCT is at the same bandwidth, so that qualifier is not established by our copy. (LLM, conf=0.83)

  cites [24] Dowling, 2008, Quantum optical metrology—the lowdown on high-N00N states, Contemp. Phys. sourceExperimental — accuracy not yet measured

In the paper

“In order to overcome the impracticality of this scheme, the measurement-device-independent (MDI) QKD protocol has been proposed [84], where all detector side channels attacks are now removed.”

What the sources say

• ?Could not verify

  The supplied Abstract passages describe Hong–Ou–Mandel interference between fields from remote atomic memories, not an MDI-QKD protocol. Searches of our copy for MDI QKD, detector side-channel attacks, and QKD detector security found no passage addressing the attributed claim. The passages have no page labels in our copy. (LLM, conf=0.78)

  cites [84] Chaneliere, 2007, Quantum interference of electromagnetic fields from remote quantum memories, Phys. Rev. Lett. sourceExperimental — accuracy not yet measured

In the paper

“Further experimental demonstrations of QOCT have also been reported, where micron-sized features are detected even for the case of biological samples [26][27][28].”

What the sources say

• ?Not checked — no full text of the sourcecites [26] Zeilinger, 1998, Quantum entanglement: a fundamental concept finding its applications, Phys. Scr. T source
• ?Could not verify

  The paper’s main text describes Hong–Ou–Mandel coalescence and cloning of orbital-angular-momentum photon qubits; its Experimental setup section describes photon preparation and detection. Neither addresses quantum optical coherence tomography, micron-sized features, or biological samples (searched those terms and related imaging terms). Page numbers were not available in our copy. (LLM, conf=0.76)

  cites [27] Nagali, 2009, Optimal quantum cloning of orbital angular momentum photon qubits through Hong–Ou–Mandel coalescence, Nat. Photon. sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [28] Karimi, 2014, Exploring the quantum nature of the radial degree of freedom of a photon via Hong–Ou–Mandel interference, Phys. Rev. A source

In the paper

“It is shown in [111] that this can be rewritten as a superposition of symmetric and antisym- metric Bell states”

What the sources say

• ?Could not verify

  The passage discussing Eq. (2) considers one photon from Alice and one from Bob entering a beam splitter, and Eq. (3) describes possible detector states after interference. Our copy does not state that any such input state can be rewritten as a superposition of symmetric and antisymmetric Bell states; searches for those terms found no passage addressing that decomposition. (LLM, conf=0.72)

  cites [111] Guan, 2015, Experimental passive round-robin differential phase-shift quantum key distribution, Phys. Rev. Lett. sourceExperimental — accuracy not yet measured

In the paper

“However, it has recently been shown that by considering the limits dictated by statistical estimation theory, it is possible to push the time resolution of a HOM interferometer to sub-femtosecond resolutions [20].”

What the sources say

• ?Could not verify

  The experimental description (section (3), page unavailable) reports pulse delays of 533–933 femtoseconds and measurements of interference visibility. A search for statistical estimation theory, sub-femtosecond resolution, and delay precision found no passage establishing the claimed resolution limit. (LLM, conf=0.76)

  cites [20] Kim, 1999, Quantum interference by two temporally distinguishable pulses, Phys. Rev. A sourceExperimental — accuracy not yet measured

In the paper

“An example of a 3-dimensional image taken via QOCT for the skin of an onion coated in gold is shown in Fig. 3; this result indicates a resolution of 1 µm.”

What the sources say

• ?Could not verify

  The paper’s Conclusions discuss interference between photons of different colors and frequency conversion, not QOCT imaging. Searches for QOCT, onion skin, gold nanoparticles, and a 1 µm imaging resolution found no passage addressing the claimed image or resolution. (LLM, conf=0.78)

  cites [33] Raymer, 2010, Interference of two photons of different color, Opt. Commun. sourceExperimental — accuracy not yet measured

In the paper

“For example, an arbitrary polarization qubit |1 s = α |1 H + β |1 V , where |α| 2 + |β| 2 = 1, can be optimally cloned using the HOM effect by interfering it on a beam splitter with an ancilla that is in a maximally mixed polarization state”

What the sources say

• ?Could not verify

  The Overview of Experiment and Protocol describes microwave photons interfering at a beam-splitter equivalent, and the Error Analysis mentions Hong–Ou–Mandel interference. Neither passage addresses cloning a polarization qubit with a maximally mixed ancilla. Searches for optimal cloning, polarization, and a mixed-state ancilla found no passage supporting that claim. (LLM, conf=0.76)

  cites [114] Narla, 2016, Robust concurrent remote entanglement between two superconducting qubits, Phys. Rev. X sourceExperimental — accuracy not yet measured
• Partly supported

  The section on entanglement creation and swapping based on two-photon detections describes HOM interference when photons meet at a beam splitter. It does not say that this effect optimally clones an arbitrary polarization qubit or describe an ancilla in a maximally mixed polarization state. (LLM, conf=0.83)

  cites [115] Sangouard, 2011, Quantum repeaters based on atomic ensembles and linear optics, Rev. Mod. Phys. sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [116] Briegel, 1998, Quantum repeaters: the role of imperfect local operations in quantum communication, Phys. Rev. Lett. source
• ?Could not verify

  The section on intercept-and-resend attacks discusses quantum-state discrimination, while Appendix A addresses QBER minimization; neither describes polarization-qubit cloning. Searches for HOM interference, a beam splitter, and a maximally mixed ancilla found no passage addressing the claimed procedure. Page numbers were not available in our copy. (LLM, conf=0.74)

  cites [117] Fung, 2007, Phase-remapping attack in practical quantum-key-distribution systems, Phys. Rev. A sourceExperimental — accuracy not yet measured

In the paper

“In order to overcome the difficulties in achieving stable variable-delay interferometers, a passive version of the RRDPS QKD was proposed [85].”

What the sources say

• ?Could not verify

  The paper describes synchronized single-photon sources and photonic entanglement (p. 1), not a passive RRDPS QKD proposal. Searches for RRDPS, passive QKD, and variable-delay interferometers found no passage addressing the attributed claim. (LLM, conf=0.75)

  cites [85] Yuan, 2007, Synchronized independent narrow-band single photons and efficient generation of photonic entanglement, Phys. Rev. Lett. sourceExperimental — accuracy not yet measured

In the paper

“For the case of N = 2 [36,37], we recognize the state from Eq. ( 5) where two indistinguishable photons are made incident onto both input ports of a 50:50 BS, resulting in HOM interference.”

What the sources say

• Partly supported

  The paper’s HOM-interference discussion (section labeled Abstract; page unavailable) describes one photon entering each beam-splitter input and both emerging from the same output when their arrival times match. It does not identify the output as an N00N state or specify a 50:50 beam splitter. (LLM, conf=0.88)

  cites [36] Giovannini, 2015, Spatially structured photons that travel in free space slower than the speed of light, Science sourceExperimental — accuracy not yet measured
• Partly supported

  The Experimental results section discusses a hypothetical two-photon Hong–Ou–Mandel experiment and its expected interference dip. It does not describe preparing an N=2 N00N state by sending indistinguishable photons into both input ports of a 50:50 beam splitter; its example instead involves partially distinguishable photons. (LLM, conf=0.78)

  cites [37] Bouchard, 2016, Observation of subluminal twisted light in vacuum, Optica sourceExperimental — accuracy not yet measured

In the paper

“By doing so, an average accuracy and average precision of 6 attoseconds and 16 attoseconds were achieved, respectively.”

What the sources say

• ?Could not verify

  The experimental description in section (3) reports pulse widths and delays in femtoseconds, but gives no average accuracy or precision in attoseconds. Searches for the claimed 6- and 16-attosecond figures and for accuracy and precision found no passage addressing those results. (LLM, conf=0.75)

  cites [20] Kim, 1999, Quantum interference by two temporally distinguishable pulses, Phys. Rev. A sourceExperimental — accuracy not yet measured

In the paper

“Indeed, the HOM visibility has been used to characterize the level of mode indistinguishability for a wide range of single photon sources, i.e. spontaneous parametric down-conversion [52,53], quantum dots [54][55][56][57][58], atomic vapours [59][60][61][62][63], nitrogen-vacancy centres in diamond [64][65][66], trapped ions [67], trapped neutral atoms [68,69], and molecules [70,71].”

What the sources say

• ?Not checked — no full text of the sourcecites [52] Lopez-Mago, 2012, Quantum-optical coherence tomography with collinear entangled photons, Opt. Lett. source
• ?Could not verify

  The quantum-OCT discussion (page unavailable) describes an HOM dip and a coincidence-counting signature for SPDC biphotons. It does not address using HOM visibility to characterize mode indistinguishability. Searches for visibility and indistinguishability found no passage supporting that use or the stated range of single-photon sources. (LLM, conf=0.72)

  cites [53] Erkmen, 2006, Phase-conjugate optical coherence tomography, Phys. Rev. A sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [54] Banaszek, 2007, Blind dispersion compensation for optical coherence tomography, Opt. Commun. source
• ?Could not verify

  The Applications in Quantum interferometry section (p. 5) discusses Mach–Zehnder phase estimation and NOON states, not HOM visibility as a measure of photon-mode indistinguishability. Searches for “HOM visibility,” “Hong-Ou-Mandel visibility,” and mode indistinguishability found no passage addressing its use across single-photon sources. (LLM, conf=0.75)

  cites [59] Giovannetti, 2011, Advances in quantum metrology, Nat. Photon. sourceExperimental — accuracy not yet measured

In the paper

“Several schemes have thus been proposed to achieve high photon number N00N states experimentally [38][39][40][41] along with experimental demonstrations [42][43][44][45][46][47][48][49][50][51], where most of these schemes are in the spirit of the two-photon, or more generally multi-photon, interference set by the HOM effect.”

What the sources say

• ?Could not verify

  The Introduction (page unavailable) describes two-photon Hong–Ou–Mandel interference used to measure structured photons’ transit time. Searches for N00N states and high-photon-number schemes found no passage addressing whether most such schemes rely on HOM-type interference. (LLM, conf=0.75)

  cites [38] Lyons, 2018, How fast is a twisted photon?, Optica sourceExperimental — accuracy not yet measured
• Partly supported

  The Introduction identifies the HOM effect as two-photon interference, and the Conclusion reports an experimental demonstration of HOM-type fringes. Neither passage describes a high-photon-number N00N state or establishes that most schemes for producing such states use HOM-type interference; those parts of the citing sentence are not supported by this source. (LLM, conf=0.84)

  cites [42] Kim, 2017, Two-photon interference of polarization-entangled photons in a Franson interferometer, Sci. Rep. sourceExperimental — accuracy not yet measured
• Partly supported

  The Experimental Arrangement (page not provided) describes interference between entangled photon pairs and coincidence detection, supporting the two-photon-interference aspect. The paper reports quantum optical coherence tomography of a biological sample, not high-photon-number N00N-state generation or a survey establishing that most such schemes follow the HOM effect. (LLM, conf=0.83)

  cites [51] Nasr, 2009, Quantum optical coherence tomography of a biological sample, Opt. Commun. sourceExperimental — accuracy not yet measured

In the paper

“For instance, several side channel attacks have been demonstrated experimentally, showing the vulnerability of the commercial QKD systems under study [93,94].”

What the sources say

• ?Could not verify

  The main text and the 'Classical Memories and Coherent Input Pulses' section discuss intercept–resend attacks only as a comparison for quantum-memory fidelity. Searches for experimental side-channel attacks and commercial QKD systems found no passage reporting demonstrations or vulnerabilities of commercial systems. Page numbers were not available in our copy. (LLM, conf=0.76)

  cites [93] Specht, 2011, A single-atom quantum memory, Nature sourceExperimental — accuracy not yet measured
• ?Could not verify

  The paper’s Abstract reports two-photon interference using photons emitted by a single molecule, not attacks on QKD systems. Searches for side-channel attacks and commercial QKD security found no passage addressing the attributed claim. (LLM, conf=0.78)

  cites [94] Kiraz, 2005, Indistinguishable photons from a single molecule, Phys. Rev. Lett. sourceExperimental — accuracy not yet measured

In the paper

“In particular, it is the even-order effects of dispersion, such as group-velocity dispersion, that are cancelled [22].”

What the sources say

• ?Could not verify

  Section 2 discusses measurements on two particles and their wave functions, not optical dispersion. Searches for even-order dispersion, group-velocity dispersion, and two-photon interference found no passage in our copy addressing the claimed cancellation. (LLM, conf=0.76)

  cites [22] Einstein, 1935, Can quantum-mechanical description of physical reality be considered complete?, Phys. Rev. sourceExperimental — accuracy not yet measured

In the paper

“the correlation noise properties at the outputs were studied and found to be below the random partition noise, i.e. classically expected noise (see Fig. 10a).”

What the sources say

• ?Could not verify

  The Experimental boson sampling section (pp. 3–4) reports output probability distributions for one-, two-, and three-photon experiments, but does not compare output correlation noise with random partition noise. Searches for those terms and for classical or distinguishable-particle noise comparisons found no passage establishing the claimed result. (LLM, conf=0.76)

  cites [199] Crespi, 2013, Integrated multimode interferometers with arbitrary designs for photonic boson sampling, Nat. Photon. sourceExperimental — accuracy not yet measured

In the paper

“and as such a proof for atomic bunching [193].”

What the sources say

• Partly supported

  In “C. Interpretation and consequences” (page unavailable), the paper states that bosons have an average tendency to bunch. That supports the bunching aspect, but the passage does not establish a proof specifically for atomic bunching. (LLM, conf=0.82)

  cites [193] Tichy, 2013, Limits to multipartite entanglement generation with bosons and fermions, Phys. Rev. A sourceExperimental — accuracy not yet measured

In the paper

“This post-selection process renders the NS gate to be probabilistic, with a success probability of p NS = 1/4 for an arbitrary input state without feedforward.”

What the sources say

• ?Could not verify

  The Abstract discusses interference between photons from independent sources and mentions KLM-type quantum computing, but does not describe an NS gate. Searches for the NS gate, post-selection, feedforward, and a 1/4 success probability found no passage addressing the claimed probability or its conditions. (LLM, conf=0.74)

  cites [76] Kaltenbaek, 2006, Experimental interference of independent photons, Phys. Rev. Lett. sourceExperimental — accuracy not yet measured

In the paper

“actual plasmonic bunching was experimentally observed in 2013 [180].”

What the sources say

• Partly supported

  The Figure 4 passage reports experimentally measured spatial bunching in thermal light, and the Abstract describes experiments in nonlinear photonic lattices. Neither passage identifies the effect as plasmonic or reports an observation in 2013, so those parts of the claim are unsupported. (LLM, conf=0.84)

  cites [180] Lahini, 2012, Quantum walk of two interacting bosons, Phys. Rev. A sourceExperimental — accuracy not yet measured

In the paper

“For three photons for example, an additional collective phase is required to describe the photons' scattering behaviour [146][147][148].”

What the sources say

• ?Could not verify

  The ‘Quantum state fusion in photons’ passages describe a three-photon fusion apparatus, while ‘Additional information’ models imperfect indistinguishability between three photons. Neither states that an additional collective phase is required to describe three-photon scattering; searches for that phase and for a triad phase found no supporting passage in our copy. (LLM, conf=0.75)

  cites [146] Vitelli, 2013, Joining the quantum state of two photons into one, Nat. Photon. sourceExperimental — accuracy not yet measured
• ?Could not verify

  Section IV discusses three-photon entangled states in relation to quantum-state joining, not a collective phase needed to describe scattering. A search of the indexed copy for collective phase and three-photon scattering found no passage addressing that claim. (LLM, conf=0.75)

  cites [147] Passaro, 2013, Joining and splitting the quantum states of photons, Phys. Rev. A sourceExperimental — accuracy not yet measured
• ?Could not verify

  The Introduction (page unavailable) defines nonlinear and conditional sign-shift gates, and Section III (page unavailable) applies a conditional sign shift to a two-photon state across three modes. Neither passage addresses three-photon scattering or says that describing it requires an additional collective phase. Searches for those terms found no supporting passage in our copy. (LLM, conf=0.76)

  cites [148] Knill, 2003, Bounds on the probability of success of postselected nonlinear sign shifts implemented with linear optics, Phys. Rev. A sourceExperimental — accuracy not yet measured

In the paper

“The first such interference was studied in 1998 with a constant stream of colliding electrons produced in a two-dimensional electron gas [196].”

What the sources say

• ?Could not verify

  The paper’s two-photon interference discussion (p. 4) concerns photons in a boson-sampling circuit, not colliding electrons. Searches for fermionic interference, a two-dimensional electron gas, and the claimed 1998 experiment found no passage addressing that history. (LLM, conf=0.78)

  cites [196] Broome, 2013, Photonic boson sampling in a tunable circuit, Science sourceExperimental — accuracy not yet measured

In the paper

“If one electron is delayed, the noise properties change such that a Pauli-dip (analog to the HOM-dip for coincidences measurements) of around 50% of the classical noise level was observed.”

What the sources say

• ?Could not verify

  The experimental-results section (p. 3) describes Hong–Ou–Mandel interference between photons, not delayed electrons or a Pauli dip. Searches for a delayed electron, Pauli dip, and a 50% classical noise level found no passage addressing the claimed observation. (LLM, conf=0.77)

  cites [199] Crespi, 2013, Integrated multimode interferometers with arbitrary designs for photonic boson sampling, Nat. Photon. sourceExperimental — accuracy not yet measured

In the paper

“The most efficient CZ gate has a success probability of 2/27, utilizing two single photon ancillary modes and only four BS [126].”

What the sources say

• ?Could not verify

  The source describes measurement-device-independent quantum key distribution, including a Bell-state measurement using a beam splitter (p. 4). Searches for a CZ gate, a 2/27 success probability, ancillary photons, and four beam splitters found no passage addressing the claimed gate design. (LLM, conf=0.76)

  cites [126] Yin, 2016, Measurement-device-independent quantum key distribution over a 404 km optical fiber, Phys. Rev. Lett. sourceExperimental — accuracy not yet measured

In the paper

“Although the statistical significance of the fidelity was too small to exclude classical explanations with certainty (0.52±0.03)”

What the sources say

• ?Could not verify

  The passage discussing Fig. 2(b) reports visibility in a two-photon waveguide experiment, not fidelity in a phonon experiment. Searches for phonon fidelity, 0.52±0.03, and statistical significance found no passage addressing the claimed result. The paper’s finding that its own visibility exceeded a classical bound does not establish or refute the claim about the phonon experiment. (LLM, conf=0.76)

  cites [181] Poem, 2012, Two-photon path-entangled states in multimode waveguides, Phys. Rev. Lett. sourceExperimental — accuracy not yet measured

In the paper

“it has been shown that not only bosons but also fermions in the form of electrons can interfere in an HOM-like arrangement.”

What the sources say

• ?Could not verify

  The paper describes Hong–Ou–Mandel-style measurements with two input photons (p. 3) and reports two-photon interference (p. 4). Searches for electrons and fermionic HOM-like interference found no passage addressing the claimed electron result. (LLM, conf=0.78)

  cites [196] Broome, 2013, Photonic boson sampling in a tunable circuit, Science sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [197] Spring, 2012, Boson sampling on a photonic chip, Science source
• ?Could not verify

  The Introduction (p. 1) describes Hong–Ou–Mandel interference between photons, and the Results (p. 3) report three-photon interference. Searches for electrons, fermions, and HOM-like electron interference found no passage in our copy addressing whether electrons can interfere in such an arrangement. (LLM, conf=0.75)

  cites [198] Tillmann, 2013, Experimental boson sampling, Nat. Photon. sourceExperimental — accuracy not yet measured

In the paper

“Furthermore, similar concepts and results, such as a zero-transmission law for various output distributions, can also be generalized to n bosons sent in the n ports of a Bell-multiport [149][150][151][152].”

What the sources say

• ?Could not verify

  Section III (p. 3) discusses conditional photon detection in an NS gate, and Section IV (pp. 4–6) discusses a CNOT gate and Bell states. Neither addresses a zero-transmission law or n bosons entering the n ports of a Bell-multiport; searches for those terms and for output-distribution suppression found no supporting passage. (LLM, conf=0.77)

  cites [149] Raplh, 2001, Simple scheme for efficient linear optics quantum gates, Phys. Rev. A sourceExperimental — accuracy not yet measured
• ?Could not verify

  The passages describing the beam-splitter setup and output states (indexed under Abstract; page unavailable) concern a nondeterministic quantum logic gate. Searches for the zero-transmission law and for n bosons entering the n ports of a Bell-multiport found no passage addressing that generalization. (LLM, conf=0.76)

  cites [150] Zou, 2002, Teleportation implementation of nondeterministic quantum logic operations by using linear optical elements, Phys. Rev. A sourceExperimental — accuracy not yet measured
• ?Could not verify

  Section 3.2 discusses general N-mode beam-splitter networks and conditional photon-detection outcomes, but does not state a zero-transmission law. A search of our copy for that law and for n bosons entering the ports of a Bell-multiport found no passage addressing the claimed generalization. (LLM, conf=0.72)

  cites [151] Scheel, 2004, Quantum gates and decoherence sourceExperimental — accuracy not yet measured
• ?Could not verify

  The Introduction and Section III discuss postselected linear-optical gates and conditional phase shifts; Section IV addresses bounds on those gates. Searches for a zero-transmission law and for n bosons entering the n ports of a Bell-multiport found no passage addressing either point in our copy. (LLM, conf=0.73)

  cites [152] Knill, 2002, Quantum gates using linear optics and postselection, Phys. Rev. A sourceExperimental — accuracy not yet measured

In the paper

“Perhaps surprisingly, the analogy between them goes all the way down to formal equivalence: the HOM effect is an optical implementation of the (destructive) SWAP test [135].”

What the sources say

• Partly supported

  The Introduction describes HOM interference as an optical measurement in which coincidence events indicate distinguishable photon states. The phase-state analysis likewise relates coincidences to perturbations of the incoming state. Our copy does not identify this measurement as a destructive SWAP test or establish the claimed formal equivalence. (LLM, conf=0.82)

  cites [135] Islam, 2019, Scalable high-rate, high-dimensional time-bin encoding quantum key distribution, Quantum Sci. Technol. sourceExperimental — accuracy not yet measured

In the paper

“Because levitons are propagating with less disturbance, the visibility of the interference is significantly higher than the one of the electronic HOM interference described in the last paragraph (see Fig. 10b)).”

What the sources say

• ?Could not verify

  The Results section describes interference between photons in a boson-sampling experiment, but does not compare leviton interference with electronic Hong–Ou–Mandel interference. Searches for levitons and electronic HOM visibility found no passage addressing the claimed difference. (LLM, conf=0.75)

  cites [201] Bentivegna, 2015, Experimental scattershot boson sampling, Sci. Adv. sourceExperimental — accuracy not yet measured

In the paper

“From the noise measurements, a g (2) value up to 1 was deduced if both levitons were emitted simultaneously, which is a signature for antibunching.”

What the sources say

• ?Could not verify

  The Methods section describes validation of photon-sampling data, and the Discussion mentions noise from incorrectly heralded photons. Neither addresses levitons or a g(2) value deduced from noise measurements. Searches for levitons, g(2), and antibunching found no passage supporting the claim. (LLM, conf=0.78)

  cites [201] Bentivegna, 2015, Experimental scattershot boson sampling, Sci. Adv. sourceExperimental — accuracy not yet measured

In the paper

“it still inspires physicists to study its connection to novel systems such as quantized spin waves, i.e. magnons [207], Bogoliubov quasiparticles [208], massless Dirac fermions in topological insulators and graphene [209] or to transfer the idea to analog situations, e.g. with bright solitons [210].”

What the sources say

• ?Not checked — no full text of the sourcecites [207] Wang, 2012, Hong–Ou–Mandel interference mediated by the magnetic plasmon waves in a three-dimensional optical metamaterial, Opt. Express source
• ?Could not verify

  Split into 2 atoms — 0 confirmed, 0 partially supported, 0 disputed, 0 misattributed, 2 unverifiable. Expand the claim to see per-atom verdicts.

  cites [208] Heeres, 2013, Quantum interference in plasmonic circuits, Nat. Nanotechnol. sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [209] Toyoda, 2015, Hong-Ou-Mandel interference of two phonons in trapped ions, Nature source

In the paper

“Nevertheless, destructive and constructive interference can be adjusted by tailoring the symmetry of the overall input two-photon state”

In the paper

“While for completely distinguishable states, i.e. φ| ψ = 0, the two photons will bunch half of the time.”

In the paper

“For the |Ψ + state, we may notice that the output photons always exit the BS together through the same output ports, just as in the case of indistinguishable photons discussed previously, i.e. |1 a |1 b .”

In the paper

“In the second case, we have one photon per detector”

In the paper

“Overall, the cloning fidelity is then F cloning = 2 3 × 1 + 1 3 × 1 2 = 5 6”

In the paper

“We note that when |φ and |ψ are identical there will be no coincidences and the last term in Eq (8) will vanish.”

In the paper

“With no surprises, we obtain all the classically expected outcomes.”

In the paper

“In a two-photon interference experiment, maximal interference occurs when the input photons are indistinguishable at both input ports of the BS.”

In the paper

“Analog to the two-photon HOM effect, if three indistinguishable photons are sent into the three input ports, not all possible output-distributions will be realized.As can be seen in Figure 7a for a three-dimensional Bell-port, bosonic coalescence leads to only 4 out of 10 possible output distributions.”

What the sources say

• Not checked yet

  Checked before — its earlier verdict is held back until a new check runs.

  cites [141] Navez, 2003, Cloning a real d-dimensional quantum state on the edge of the no-signaling condition, Phys. Rev. A source

In the paper

“In the aforementioned implementations of MDI QKD, to achieve high secret key rates, attenuated laser pulses were employed along with the decoy state protocol [101].”

What the sources say

• ?Not checked — no full text of the sourcecites [101] Grice, 2011, Arbitrarily complete bell-state measurement using only linear optical elements, Phys. Rev. A source

In the paper

“Finally, it has recently been shown that the passive RRDPS protocol could also be extended to other high-dimensional QKD protocols [108].”

What the sources say

• ?Not checked — no full text of the sourcecites [108] Bennett, 1992, Communication via one- and two-particle operators on Einstein–Podolsky–Rosen states, Phys. Rev. Lett. source

In the paper

“Subpicosecond time intervals can now be measured for photon pairs from parametric down-conversion going far beyond the previous timing resolution of standard photodetectors, i.e. larger than 100 ps.”

What the sources say

• ?Not checked — no full text of the sourcecites [4] Hong, 1987, Measurement of subpicosecond time intervals between two photons by interference, Phys. Rev. Lett. source

In the paper

“Since then, several experiments have investigated the use of the HOM effect to perform precise timing measurements.”

In the paper

“In particular, the security of the RRDPS protocol is largely enhanced when considering large dimensions; therefore, it is worth exploring different implementations achieving larger dimensions.”

In the paper

“For twoqubit gates where interaction is required, the HOM effect is relied heavily upon.”

In the paper

“they note that, for a balanced beam splitter, the simultaneous detections at the two output ports behaves like the singlet state for two orthogonally polarized photons, i.e., a Bell state measurement, as we know it today.”

What the sources say

• ?Not checked — no full text of the sourcecites [3] Ou, 1987, Relation between input and output states for a beam splitter, Opt. Commun. source

In the paper

“Finally, another field of research where the HOM effect plays an essential role for precision measurement is quantum metrology”

In the paper

“Once again, the HOM effect is used as a highly precise timing measurement tool.”

In the paper

“For example, if we use exclusively linear optics and no other ancillary modes, we are bound to a 50% discrimination success rate [72].”

What the sources say

• Not checked yet

  Checked before — its earlier verdict is held back until a new check runs.

  cites [72] Okamoto, 2008, Beating the standard quantum limit: phase super-sensitivity of N-photon interferometers, New J. Phys. source

In the paper

“The Knill-Laflamme-Milburn (KLM) linear optical implementation of the CNOT quantum gate, which will be discussed in detail in Sec.VI A, plays the key role for achieving quantum state joining.”

What the sources say

• Not checked yet

  Checked before — its earlier verdict is held back until a new check runs.

  cites [76] Kaltenbaek, 2006, Experimental interference of independent photons, Phys. Rev. Lett. source

In the paper

“Nevertheless, practical implementations do not necessarily follow the assumptions made in the security proofs.”

In the paper

“It was found that a CZ gate can be constructed using two 50:50 BS and two so-called nonlinear sign (NS) gates [76], see Fig. 5a).”

What the sources say

• Not checked yet

  Checked before — its earlier verdict is held back until a new check runs.

  cites [76] Kaltenbaek, 2006, Experimental interference of independent photons, Phys. Rev. Lett. source

In the paper

“Therefore, when conditioning on coincidence detection between the two output ports, the HOM effect acts as a filter for the antisymmetric component for any arbitrary high-dimensional input state.”

In the paper

“This idea can be applied to other domains as well, for example to entangle a pair of transmon qubits by interfering two microwave photons at a microwave beam splitter junction [88].”

What the sources say

• Not checked yet

  Checked before — its earlier verdict is held back until a new check runs.

  cites [88] Bernien, 2012, Two-photon quantum interference from separate nitrogen vacancy centers in diamond, Phys. Rev. Lett. source

In the paper

“Thus, security loopholes have, early on, been recognized to pose a threat to the security of realistic QKD implementations [91,92].”

What the sources say

• Not checked yetcites [91] Maunz, 2007, Quantum interference of photon pairs from two remote trapped atomic ions, Nat. Phys. source
• ?Not checked — no full text of the sourcecites [92] Beugnon, 2006, Quantum interference between two single photons emitted by independently trapped atoms, Nature source

In the paper

“Dimensions ranging between 5 and 128 have been achieved in the time-bin configuration using interferometers with variable delays.”

In the paper

“In order to overcome the resolution limitations, a technique known as quantum optical coherence tomography (QOCT) has been proposed to exploit the automatic dispersion cancellation involved in the two-photon interference effect [24].”

What the sources say

• Not checked yetcites [24] Dowling, 2008, Quantum optical metrology—the lowdown on high-N00N states, Contemp. Phys. source

In the paper

“Thus, one can already appreciate the importance of the HOM effect in quantum metrology relying on the entanglement of multi-photon states.”

In the paper

“Hence, the ability to discriminate the |Ψ -Bell state, by taking advantage of its fermionic behaviour, is central to the concept of Bell state analysis”

In the paper

“The resolution in space and phase is enhanced by a factor of N, i.e. scales as 1/N.”

What the sources say

• ?Not checked — no full text of the sourcecites [12] Ou, 1989, Fourth-order interference technique for determining the coherence time of a light beam, J. Opt. Soc. Am. B source

In the paper

“The action of the beam splitter (BS) is at the heart of the two-photon interference effect, providing the mixing between the two input modes.”

In the paper

“It is possible to combine N interferences and raise the success rate to 1 -2 -N .”

In the paper

“Thus, the two-photon interference effect holds great potential for applications where dispersion can seriously limit optical applications.”

In the paper

“If successful, this procedure has swapped the entanglement from being between each atom and its photon to being between the two atoms alone.”

What the sources say

• Not checked yet

  Checked before — its earlier verdict is held back until a new check runs.

  cites [86] Yuan, 2008, Experimental demonstration of a bdcz quantum repeater node, Nature source

In the paper

“Thus, HOM can be adopted as a powerful tool to directly measure the overlap between two single photon wavepackets.”

In the paper

“The simplest implementation uses only one interference at a single beam splitter and two detectors.”

In the paper

“Experimentally, quantum state joining has been achieved for the polarization state of two photons, in which the information was transferred onto a third single photon by exploiting the fact that a single particle can occupy different spatial modes and polarizations [120].”

What the sources say

• Not checked yet

  Checked before — its earlier verdict is held back until a new check runs.

  cites [120] Gerhardt, 2011, Full-field implementation of a perfect eavesdropper on a quantum cryptography system, Nat. Commun. source

In the paper

“Thus, in order to achieve the fundamental quantum limit, also known as the Heisenberg limit, for phase sensitivity, one must consider high photon number N00N states.”

In the paper

“which redistributes the three incoming photons to the three output ports in an unbiased way.”

What the sources say

• Not checked yet

  Checked before — its earlier verdict is held back until a new check runs.

  cites [139] Zhao, 2014, Entangling different-color photons via time-resolved measurement and active feed forward, Phys. Rev. Lett. source
• Not checked yet

  Checked before — its earlier verdict is held back until a new check runs.

  cites [140] Peres, 2003, How the no-cloning theorem got its name, Fortschr. Phys. source

In the paper

“the result is a nice indication of a two plasmons quantum interference.”

In the paper

“Thus, it has to be considered a genuine three-photon interference effect with no analog in the standard HOM experiment.”

In the paper

“For waiting times when the hopping probability of the phonons was 50%, bunching was observed (see Fig. 8c and d).”

What the sources say

• Not checked yet

  Checked before — its earlier verdict is held back until a new check runs.

  cites [181] Poem, 2012, Two-photon path-entangled states in multimode waveguides, Phys. Rev. Lett. source

In the paper

“another recent experiment demonstrated that there are additional features unique to multi-partite interferences [144].”

What the sources say

• ?Not checked — no full text of the sourcecites [144] De Martini, 2002, Experimental realization of the quantum universal not gate, Nature source

In the paper

“The upper bound for the NS gate was found to be 1/2 [122].”

What the sources say

• Not checked yet

  Checked before — its earlier verdict is held back until a new check runs.

  cites [122] Acín, 2007, Device-independent security of quantum cryptography against collective attacks, Phys. Rev. Lett. source

In the paper

“It has been shown that calculating the output probability distribution for a sufficiently large number of photons interfering in a large multiport arrangement is exponentially hard to solve classically”

What the sources say

• ?Not checked — no full text of the sourcecites [166] Żukowski, 1997, Realizable higher-dimensional two-particle entanglements via multiport beam splitters, Phys. Rev. A source
• ?Not checked — no full text of the sourcecites [167] Campos, 2000, Three-photon Hong–Ou–Mandel interference at a multiport mixer, Phys. Rev. A source

In the paper

“Similar to the two photon HOM-interference, three photons can interfere in a tritter if they are indistinguishable.”

In the paper

“A nice example recently demonstrated a quantum walk with phonons implemented in a trapped ion crystal [189].”

What the sources say

• Not checked yetcites [189] Tillmann, 2015, Generalized multiphoton quantum interference, Phys. Rev. X source

In the paper

“It is also possible to implement the NS gate in the polarization basis, wherein polarization rotations are used instead of the variable BS; this also has a success probability of (3 -√ 2)/7.”

In the paper

“a multiphoton interference in a multiport has enabled the first quantum teleportation of a high-dimensional quantum state [164].”

What the sources say

• ?Not checked — no full text of the sourcecites [164] Weihs, 1996, Two-photon interference in optical fiber multiports, Phys. Rev. A source

In the paper

“However, the property of multiphoton interference is not limited to this rather simple (and yet powerful) case, but it can be generalized to more particles in more complicated beam splitter networks with multipleinput and multiple-output ports, i.e. so-called multiports.”

In the paper

“In the experiment, a three-dimensional quantum state was teleported using one additional ancillary photon.”

What the sources say

• ?Not checked — no full text of the sourcecites [164] Weihs, 1996, Two-photon interference in optical fiber multiports, Phys. Rev. A source

In the paper

“It is possible to achieve a useful quantum computation without resorting to a universal quantum computer.In this case, it is sufficient to have a device that performs a single algorithm.”

In the paper

“This is sufficient to conclude with a full analogy between the HOM effect and the SWAP test.”

In the paper

“This suggests that one could also implement a destructive SWAP test by measuring directly the two systems in the Bell basis.”

In the paper

“collective excitations have also been tested with respect to interference effects in a recent experiment using a Rb ensemble [182].”

What the sources say

• Not checked yetcites [182] Defienne, 2016, Two-photon quantum walk in a multimode fiber, Sci. Adv. source

In the paper

“Shortly after this initial step, these results were extended to a complex quantum walk of atoms in a two-dimensional optical lattice [191].”

What the sources say

• Not checked yet

  Checked before — its earlier verdict is held back until a new check runs.

  cites [191] Ferreri, 2019, Temporally multimode four-photon Hong–Ou–Mandel interference, Phys. Rev. A source

In the paper

“which can be considered a clear indication for bunching of massive systems.”

In the paper

“two laser-cooled Rb atoms trapped in an optical tweezer were perfectly controlled in all internal and external degrees of freedom, thereby making them indistinguishable [190].”

What the sources say

• Not checked yetcites [190] Metcalf, 2013, Multiphoton quantum interference in a multiport integrated photonic device, Nat. Commun. source

In the paper

“The complex interference of mutliple photon in multiports cannot only be used in teleportation schemes, it also enables the generation of multi-partite entanglement [165].”

What the sources say

• ?Not checked — no full text of the sourcecites [165] Ou, 2007 source

In the paper

“In general, the output probability distribution of the three photons depends on the input distribution as well as the exact unitary transformation of the tritter.”

In the paper

“The implementation of the CNOT gate is similar to that of the CZ gate in that it requires two NS gates; however, two additional 50:50 BS are required acting on the target qubit [127], as shown in Fig. 5.”

What the sources say

• Not checked yet

  Checked before — its earlier verdict is held back until a new check runs.

  cites [127] Lo, 2005, Decoy state quantum key distribution, Phys. Rev. Lett. source

In the paper

“Using a stimulating Raman pulse that acts as a beam splitter, the excitations can be interfered and bunched together in either of the two Zeeman states (see Fig. 8e).”

What the sources say

• Not checked yetcites [182] Defienne, 2016, Two-photon quantum walk in a multimode fiber, Sci. Adv. source

In the paper

“After appropriate postselection, the three-dimensional quantum state was found to be teleported to the photon, which was initially a part of the entangled pair.”

What the sources say

• ?Not checked — no full text of the sourcecites [164] Weihs, 1996, Two-photon interference in optical fiber multiports, Phys. Rev. A source

In the paper

“Again, since the CNOT gate is based around the NS gate, it is a probabilistic process with success probability p CNOT = p 2 NS = 1/16.”

In the paper

“the HOM interference was further applied to study an electron gas in the integer quantum Hall regime at a filling factor of 2”

What the sources say

• Not checked yetcites [200] Spagnolo, 2014, Experimental validation of photonic boson sampling, Nat. Photon. source

In the paper

“Since two NS gates are required, the total success probability of this CZ gate is p CZ = p 2 NS .”

In the paper

“Equivalently in terms of the states |φ and |ψ , if they are identically equal, the second term in the last line of Eq. ( 17) vanishes and the outcome of the measurement must be |'0' with probability 1.”

In the paper

“it has also led to many fundamental demonstrations in non-photonic systems such as plasmons, phonons, atoms and electrons.”