Multiphoton entanglement and interferometry

In the paper

“The basic idea of this experimental method is that the entangled ancillary pair was provided much more frequently than the photon to be teleported [a similar idea was also used in the teleportation experiment using time-bin entanglement carried out by Marcikic et al. (2003)].Thus, when a qubit which was to be teleported arrived the teleportation machinery was almost always ready.”

What the sources say

• Disputed

  The Experimental Realization section (p. 4) says the experiment decreased the probability of creating entangled qubits relative to the probability of creating the qubit to be teleported. That is the opposite of providing the ancillary pair much more frequently so it would almost always be ready when a qubit arrived. (LLM, conf=0.94)

  Checked by a reasoning model — may be wrong.

  cites Marcikic et al. (2003) sourceExperimental — accuracy not yet measured

In the paper

“The phase-stability problem can be overcome by interfering two photons, one coming from each remote ion or atom in a cavity (Bose et al., 1999;Browne et al., 2003;Feng et al., 2003;Simon and Irvine, 2003), which was experimentally implemented by Moehring et al., (2007) and Maunz et al., (2007).”

What the sources say

• Partly supported

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

  cites Bose et al., 1999 sourceExperimental — accuracy not yet measured
• Disputed

  Split into 2 atoms — 0 confirmed, 1 partially supported, 1 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

  Checked by a reasoning model — may be wrong.

  cites Browne et al., 2003 sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites Feng et al., 2003 source

In the paper

“Nielsen and Dawson (2005) have shown that the thresholds are respectively < 3 × 10 -3 and < 10 -4 for photon loss and depolarizing noise (see also Dawson et al. 2006).”

What the sources say

• Disputed

  The noise-model discussion (p. 22) explicitly says photon loss is omitted and that the results apply only to noise without leakage. The conclusion (p. 26) says the paper proves that finite thresholds exist, rather than providing precise numerical evaluations; it does not establish the two thresholds attributed to it. (LLM, conf=0.90)

  Checked by a reasoning model — may be wrong.

  cites Nielsen and Dawson (2005) sourceExperimental — accuracy not yet measured
• Supported

  The Conclusion (p. 25) gives the same paired thresholds: photon-loss probability below 3 × 10^-3 and depolarization probability below 10^-4 when both noise types are present. The Introduction (p. 2) clarifies that these are values in a threshold region, not separate single-noise thresholds. (LLM, conf=0.94)

  cites Dawson et al. 2006 source

In the paper

“It turned out that using the primary two-photon entanglement, by a procedure which is called entanglement swapping, one can entangle without any direct interaction particles which were independent of each other, or what is more important for us, construct entanglement of higher order ( Żukowski et al, 1993).”

What the sources say

• Supported

  The discussion following Fig. 1 says that swapping entangles initially independent signal photons through their idlers, without touching the signals. The concluding discussion adds that a similar technique can produce a source exhibiting GHZ correlations, supporting the claim about higher-order entanglement. Page numbers are unavailable in our copy. (LLM, conf=0.90)

  cites Żukowski et al, 1993 source

In the paper

“Practical versions of this technique (Zukowski et al, 1995;Rarity, 1995;Zeilinger et al, 1997) are thus the basis of all experiments with three or more entangled photons, as well as of many realizations of quantum information protocols, up to measurement based quantum computation.”

What the sources say

• Partly supported

  The Introduction and Concluding Remarks describe entanglement-swapping methods for producing three-photon GHZ states and discuss their application to quantum teleportation. They do not establish that these methods underpin all experiments with three or more entangled photons, many realizations of quantum information protocols, or measurement-based quantum computation. (LLM, conf=0.86)

  cites Zukowski et al, 1995 sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites Rarity, 1995 source
• ?Not checked — no full text of the sourcecites Zeilinger et al, 1997 source

In the paper

“Quantum teleportation (Bennett et al., 1993) enables a faithful transfer of an unknown quantum state from one location to another, using entangled states as a quantum channel.”

What the sources say

• Supported

  The passage labeled Abstract says EPR correlations assist in teleporting an intact quantum state from one place to another, even when the sender does not know the state. The paper also identifies maximally entangled states as the nonclassical channel needed for faithful teleportation. It additionally requires a classical channel; the claim does not say the entangled channel works alone. (LLM, conf=0.94)

  cites Bennett et al., 1993 source

In the paper

“In SPDC photons from a pump laser beam, within a nonlinear crystal, can spontaneously be converted into pairs that are momentum and frequency entangled, and in the so-called type-II process can be also polarization entangled (Kwiat et al., 1995).”

What the sources say

• Partly supported

  The paper’s Abstract describes spontaneous parametric down-conversion in a nonlinear crystal and says noncollinear type-II phase matching produces polarization-entangled photon pairs. It also discusses momentum correlations, but does not establish that the pairs described are momentum-entangled; it treats momentum-entangled states as distinct states into which its polarization-entangled states can be transformed. No passage found establishes the claimed frequency entanglement. (LLM, conf=0.85)

  cites Kwiat et al., 1995 sourceExperimental — accuracy not yet measured

In the paper

“A hermitian operator Ŵ is an entanglement witness if for all separable states one has Tr( Ŵ sep ) ≥ 0, whereas there exists an entangled state for which one has Tr( Ŵ ent ) < 0. Thus, via measurement of a suitably chosen witness operator one can detect entanglement.”

What the sources say

• Supported

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

  cites Horodecki et al., 1996 source
• ?Not checked — no full text of the sourcecites Terhal, 2000 source
• ?Not checked — no full text of the sourcecites Lewenstein et al., 2000 source

In the paper

“The full set of separable mixed states is a bounded convex set in a multidimensional real space of hermitian operators.Thus, any entangled state is separated from the set of separable states by a hyperplane.”

What the sources say

• Supported

  The paper defines states as positive, trace-one operators on a finite-dimensional Hilbert space (p. 3), which makes the set of states bounded in the real space of Hermitian operators. It states that separable states form a closed convex set and uses a separation theorem to obtain a real functional separating any inseparable state from that set (p. 4). (LLM, conf=0.91)

  cites Horodecki et al., 1996 source

In the paper

“An interesting feature of the theory of entanglement of mixed states is that for two three dimensional systems, or for more complicated ones, one can find states which are entangled, but from which no maximally entangled state can be distilled 10 (Horodecki, Horodecki and Horodecki, 1998).Such states are called bound entangled.”

What the sources say

• Supported

  The paper identifies inseparable states of two spin-1 particles—the two-trit, or 3 × 3, case—and shows that states with positive partial transposition cannot be distilled (pp. 2–3). It calls this nondistillable form “bound” entanglement (p. 1). (LLM, conf=0.94)

  cites Horodecki, Horodecki and Horodecki, 1998 source

In the paper

“This was extended by Horodecki Family to a fully general necessary and sufficient condition for separability, which is that a density matrix after any positive transformation (map) on one of the subsystems should remain a density operator 9 .”

What the sources say

• Partly supported

  Theorem 2 (p. 7) gives the fully general necessary and sufficient condition: applying any positive map to one subsystem must leave the operator positive. But the paper defines a density operator (state) as also having trace one (p. 3); Theorem 2 does not require the transformed operator to retain that normalization. (LLM, conf=0.90)

  cites Horodecki et al. (1996) sourceExperimental — accuracy not yet measured

In the paper

“Basic structural criteria, which decide whether a given density operator represents an entangled state, were first given by Peres (1996) and in the full form by Horodecki et al. (1996).”

What the sources say

• ?Not checked — no full text of the sourcecites Peres (1996) source
• Supported

  The discussion on p. 3 credits Peres with the partial-transposition condition and says this paper presents necessary and sufficient conditions for separability. The conclusion on p. 11 describes its result as completing Peres’ result. Because inseparability identifies an entangled mixed state, this supports the attributed progression from Peres’ criterion to the fuller Horodecki criteria. (LLM, conf=0.91)

  cites Horodecki et al. (1996) source

In the paper

“The projection of two photons into a Bell state lies at the heart for many quantum information processing protocols, such as quantum dense coding (Bennett and Wiesner, 1992), quantum teleportation (Bennett et al., 1993), and entanglement swapping ( Żukowski et al., 1993).”

What the sources say

• ?Not checked — no full text of the sourcecites Bennett and Wiesner, 1992 source
• Supported

  The citation to Bennett et al. is attached to quantum teleportation, not to dense coding or entanglement swapping. In the passage describing the teleportation procedure, Alice measures two particles jointly in the Bell-operator basis, supporting the cited example of Bell-state projection. (LLM, conf=0.91)

  cites Bennett et al., 1993 source
• Supported

  The Żukowski et al. citation is attached specifically to entanglement swapping, not to dense coding or teleportation, which have separate citations. In the section beginning “This state implies correlations violating Bell's inequality” (page not supplied), the paper says coincident detection projects two idler photons into an entangled state and calls the result entanglement swapping. (LLM, conf=0.93)

  cites Żukowski et al., 1993 source

In the paper

“The interference of indistinguishable photons enables a process called entanglement swapping and teleportation (Zukowski et al. 1993, see Section VI.C), which in turns opens up prospects of distributing of entanglement between distant matter qubits such as ions (Moehring et al. 2007) and atoms (Yuan et al. 2008).”

What the sources say

• Partly supported

  The discussion of entanglement swapping (page unavailable in our copy) explains that coincident detection of idler photons entangles previously independent signal photons; its discussion of distinguishability links path information to reduced interference. The paper mentions subcoherence-time coincidence as a requirement for quantum teleportation, but does not say that its proposed interference process enables teleportation. (LLM, conf=0.83)

  cites Zukowski et al. 1993 sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites Moehring et al. 2007 source
• ?Not checked — no full text of the sourcecites Yuan et al. 2008 source

In the paper

“Moreover, the entanglement is only perfect for photons that are emitted back to back, a loophole that could allow local hidden-variable model to explain the experimental data (Santos, 1991(Santos, , 1992)).”

What the sources say

• ?Not checked — no full text of the sourcecites Santos, 1991 source
• Partly supported

  In the indexed Abstract (page not specified), Santos says poor angular correlation makes atomic-cascade experiments unsuitable for distinguishing local hidden-variable theories from quantum mechanics, and describes a local hidden-variable model agreeing with measurable predictions. The copy does not say that entanglement is perfect only for photons emitted back to back. (LLM, conf=0.85)

  cites Santos, 1992 sourceExperimental — accuracy not yet measured

In the paper

“Polarization entanglement in type-II process was discovered by Kwiat et al. (1995).”

What the sources say

• Supported

  The paper reports a novel source that produces polarization-entangled photon pairs directly through noncollinear type-II phase matching, contrasting it with previous schemes. This supports the citing sentence’s attribution to Kwiat et al. of the type-II polarization-entanglement result. (LLM, conf=0.85)

  cites Kwiat et al. (1995) source

In the paper

“Other examples include single photons from independent trapped atoms (Beugnon et al. 2006;Maunz et al. 2007), and from remote cold atomic ensembles (Yuan et al. 2007) or independent, tunable quantum dots (Patel et al. 2010).”

What the sources say

• ?Not checked — no full text of the sourcecites Beugnon et al. 2006 source
• Partly supported

  The paper reports single-photon generation and two-photon interference from trapped atomic ions (p. 1). But its account of the interference experiment says the two ions were in the same trap (p. 2), so it does not support describing its example as photons from independently trapped atoms. The other examples in the citing sentence have separate citations. (LLM, conf=0.86)

  cites Maunz et al. 2007 sourceExperimental — accuracy not yet measured
• Supported

  The citation to Yuan et al. applies to the remote cold atomic ensembles example, not the trapped atoms or quantum dots. The paper’s Conclusion (p. 4) reports a Hong–Ou–Mandel dip for independent photons from two distant atomic ensembles. (LLM, conf=0.94)

  cites Yuan et al. 2007 source

In the paper

“A general method for making such an interference observable, and also to swap entanglement, was given by Żukowski et al. (1993), Żukowski et al. (1995), Rarity (1995) and Zeilinger et al. (1997).”

What the sources say

• Supported

  The Abstract describes subcoherence-time monitoring of idlers as a way to entangle independent signals and obtain high fringe visibility. The section beginning “This state implies correlations…” explains that coincident idler registration produces entanglement swapping; its discussion of experiment C explains how the timing condition preserves interference visibility. Page numbers are not provided in our copy. (LLM, conf=0.90)

  cites Żukowski et al. (1993) source
• Supported

  The Entanglement Swapping section describes a projection method that entangles photons from independent sources through joint detection of indistinguishable idlers. The Welcher-Weg Information and Coincidence Requirements section explains that erasing path information lets the processes interfere and produces high-visibility fringes. The paper therefore supports both parts attributed to it; page numbers are unavailable in our copy. (LLM, conf=0.93)

  cites Żukowski et al. (1995) source
• ?Not checked — no full text of the sourcecites Rarity (1995) source

In the paper

“It was experimentally realized for N = 3 (Mitchell, Lundeen, and Steinberg, 2004) and N = 4 (Walther et al., 2004) (see also other related experiments, Rarity et al., 1990b;Edamatsu et al., 2002;Sun et al., 2006;Nagata et al., 2007).”

What the sources say

• ?Not checked — no full text of the sourcecites Mitchell, Lundeen, and Steinberg, 2004 source
• Partly supported

  Only the N=4 attribution is at issue here; the N=3 experiment is cited to a different paper. Walther et al. demonstrate four-photon interference, but describe their nonlocal four-photon state as “similar to” a NOON state, not as a NOON state itself (p. 7). (LLM, conf=0.87)

  cites Walther et al., 2004 sourceExperimental — accuracy not yet measured

In the paper

“Recently, several experiments were performed to identify and quantify the experimental imperfections that contribute error to the produced multi-photon states (see Barbieri et al. 2009;Weinhold et al. 2008).”

What the sources say

• ?Not checked — no full text of the sourcecites Barbieri et al. 2009 source
• Partly supported

  The Error Model section (pp. 4–5) identifies and quantifies experimental imperfections, including higher-order photon terms, loss, and mode mismatch. This paper measures their effects on a photonic quantum-logic gate, however, rather than directly quantifying errors in produced multi-photon states. (LLM, conf=0.82)

  cites Weinhold et al. 2008 sourceExperimental — accuracy not yet measured

In the paper

“Note that source indistinguishability in principle can also be achieved with an ultra-coincidence technique, which does not require a pulsed pump, but an extremely good detection time resolution, ∆T , much sharper that the coherence time of the filtered SPDC radiation, and rejection of all events at c(+) and d(+) which are detected with time difference higher than, say, 2∆T [see Żukowski et al. (”

What the sources say

• Partly supported

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

  cites Żukowski et al. (1993) sourceExperimental — accuracy not yet measured

In the paper

“It is a tool to fully reconstruct the density matrix of a quantum systemfoot_13 .”

What the sources say

• Supported

  The Introduction (p. 2) describes tomography as finding a quantum state's density matrix from experimental data. The section on tomographically complete measurements (p. 7) gives a reconstruction procedure. The paper notes that noise can make a linearly reconstructed matrix unphysical, but this does not change tomography's stated purpose. (LLM, conf=0.91)

  cites James et al. 2001 source

In the paper

“The initial experiments using photon pairs produced in an atomic cascade to test Bell's inequalities (Freedman and Clauser, 1972;Aspect et al., 1982aAspect et al., , 1982b, see also Clauser and Shimony 1978 for more experiments) falsified Bell's inequalities, and thus challenged the local realistic world-view.”

What the sources say

• Supported

  The paper reports measuring polarization correlations in photon pairs from a calcium atomic cascade. Its results state that the measurements clearly violated the relevant Bell-type inequality and provided strong evidence against local hidden-variable theories. (LLM, conf=0.94)

  cites Freedman and Clauser, 1972 source
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Aspect et al., 1982a
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Aspect et al., 1982b

In the paper

“A toolbox for efficient witness operator construction has been created for some multi-particle states (such as GHZ, cluster, and W state, see e.g.Gühne et al. 2007), and applied in a number of multi-photon experiments (see e.g.Bourennane et al. 2004a;Kiesel et al. 2005a;Lu et al. 2007a;Wieczorek et al. 2009a).”

What the sources say

• Supported

  The introduction (p. 1) says the paper develops measurement-efficient methods for GHZ and W states and witnesses for cluster states that require little effort. The multi-photon experiments are cited separately in the citing sentence, so they are not attributed to this source. (LLM, conf=0.93)

  cites Gühne et al. 2007 source
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Bourennane et al. 2004a
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Kiesel et al. 2005a

In the paper

“Experimentally, this technique was used for two-, three-, four-photon polarization states and also hyperentangled photon pairs (White et al. 1999;Resch et al. 2005;Walther et al. 2005b;Barreiro et al. 2005).”

What the sources say

• Supported

  White et al. support the two-photon polarization-state example in the multi-citation sentence. On p. 1, they state that they used quantum state tomography to experimentally reconstruct the reduced polarization density matrix of a two-photon state. Their citation need not support the other examples assigned to the accompanying references. (LLM, conf=0.93)

  cites White et al. 1999 source
• ?Not checked — no full text of the sourcecites Resch et al. 2005 source
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Walther et al. 2005b

In the paper

“The original proposal was experimentally demonstrated by Torgerson et al. (1995) and White et al.(1999)); as in the GHZ-type experiments, the results of the experiments were fed into specific inequalities, specially derived to take into account experimental imperfections (under the fair sampling assumption, of course).”

What the sources say

• ?Not checked — no full text of the sourcecites Torgerson et al. (1995) source
• Partly supported

  On p. 3, White et al. describe an experimental test of Hardy’s proposal, give the inequality used, and report a Hardy fraction 122σ above the local-realistic bound. Footnote [16] on p. 4 says experimental realizations require inequalities because measurements have uncertainties. The copy does not specify the fair-sampling assumption or say that the inequality was specially derived to account for experimental imperfections. (LLM, conf=0.85)

  cites White et al. (1999) sourceExperimental — accuracy not yet measured

In the paper

“By exploiting entanglement one can efficiently encode classical messages (Bennett and Wiesner, 1992; section VI.A), transfer quantum information to a remote location (Bennett et al., 1993; section VI.B), entangle two remote particles that have no common past ( Żukowski et al., 1993; section VI.C), and purify a large ensemble in a less entangled states into a smaller ensemble with higher”

What the sources say

• ?Not checked — no full text of the sourcecites Bennett and Wiesner, 1992 source
• Supported

  The cited work is attached specifically to transferring quantum information to a remote location, not to the other applications in the sentence. The passage labeled Abstract says EPR correlations assist in teleporting an intact quantum state from one place to another; the copy supplies no page number. (LLM, conf=0.94)

  cites Bennett et al., 1993 source
• Supported

  The citation is attached only to the claim about entangling remote particles with no common past. The paper states that entanglement swapping can entangle particles that do not share a common past, and its discussion of the proposed setup says the entangled signal particles share no common past. (LLM, conf=0.94)

  cites Żukowski et al., 1993 source

In the paper

“The fascinating possibility of quantum teleportation was discovered by Bennett, Brassard, Crépeau, Jozsa, Peres, and Wootters (1993).”

What the sources say

• Supported

  In the passage labeled Abstract, the authors state, “Here, we show” that EPR correlations can enable teleportation of an intact quantum state. This supports attributing the discovery of that possibility to the paper’s authors. (LLM, conf=0.92)

  cites Bennett, Brassard, Crépeau, Jozsa, Peres, and Wootters (1993) source

In the paper

“In the other three cases, Bob can apply one of the unitary transformations of Eq. ( 72) to convert the state of particle 3 into the original one of particle 1.However, all this is possible only if he additionally receives via a classical communication channel a two-bit information on the (Bouwmeester et al., 1997).”

What the sources say

• Supported

  In “THE CONCEPT OF QUANTUM TELEPORTATION” (p. 3), the paper says Bob can transform particle 3 into particle 1’s original state after receiving Alice’s Bell-state result through a classical channel. It describes four possible results, for which two bits suffice; Fig. 1 (p. 2) explicitly calls Bob’s operation a unitary transformation. (LLM, conf=0.92)

  cites Bouwmeester et al., 1997 source

In the paper

“The Bell-state analysis relies on the interference of two independently created photons.Therefore, one has to guarantee that behind the BS the information which photon came from which source is completely erased.”

What the sources say

• Supported

  The Entanglement Swapping section describes overlapping photons from independent sources at beam splitters and says their joint detection projects them into an entangled state if they are indistinguishable. The Introduction identifies erasure of idler path information as a necessary condition, while the Concluding Remarks apply that requirement to a Bell-state measurement in quantum teleportation. The copy does not give page numbers for these passages. (LLM, conf=0.88)

  cites Żukowski et al. 1995 source

In the paper

“A protocol of this kind has been proposed by Popescu (1995) and was experimentally realized in Rome (Boschi et al., 1998) with a teleportation fidelity of 0.85 (1).”

What the sources say

• Supported

  Popescu explicitly proposes an optical teleportation scheme in which the state is encoded in a different degree of freedom of one entangled photon (p. 3). The experimental realization and fidelity are attributed to Boschi et al., not to Popescu, so they are not part of this verdict. (LLM, conf=0.92)

  cites Popescu (1995) source
• Partly supported

  The main text (page unavailable) says the Rome experiment used a two-photon approach first suggested by Popescu and reports teleportation results that exceeded the classical limit. However, the measured value appears only in a formula that is not decoded in our copy, so the stated fidelity of 0.85(1) cannot be verified. (LLM, conf=0.84)

  cites Boschi et al., 1998 sourceExperimental — accuracy not yet measured

In the paper

“The first is the so-called Procrustean method (Bennett et al., 1996a).It requires that the photon pairs are all in a pure non-maximally entangled state, say, |Ψ nonmax = α|H |V + β|V |H , where α and β are two known amplitudes.In this case, the scheme only in-volves local filtering operations (Gisin, 1996;Horodecki et al., 1996) on single pairs.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Bennett et al., 1996a
• ?Not checked — no full text of the sourcecites Gisin, 1996 source
• ?Could not verify

  The paper describes separability criteria for mixed states (p. 3), not the Procrustean method. Searches for local filtering, single-pair operations, and known amplitudes found no passage describing those features; the reference to Bennett et al. (References, p. 14) does not establish them. (LLM, conf=0.76)

  cites Horodecki et al., 1996 sourceExperimental — accuracy not yet measured

In the paper

“A more feasible purification scheme was proposed by Pan et al. (2001).They showed that purification does not have to entirely rely on CNOT operations.In some cases a simple linear optical element, a polarizing beam splitter, suffices (see Fig. 28b).”

What the sources say

• Partly supported

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

  cites Pan et al. (2001) sourceExperimental — accuracy not yet measured

In the paper

“Hofmann and Takeuchi, (2002) and independently Ralph et al., (2002aRalph et al., ( , 2002b) ) developed quantum gates under the restriction of what is here called a two, or four-mode case, that is the successful operation of the gate can be verified if the two photons involved are detected in certain outputs”

What the sources say

• Supported

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

  cites Hofmann and Takeuchi, 2002 source
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Ralph et al., 2002a
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Ralph et al., 2002b

In the paper

“As suggested by Pittman et al., (2001), the success of the gate can be detected by measurement of ancilla photons and this information is classically feed-forwardable.”

What the sources say

• Supported

  The discussion of Eq. (A3) says detector outcomes identify successful CNOT operations and can trigger classically controlled corrections to the output qubits. The discussion of Eq. (A2) identifies the measured photons as occupying detection modes, while Section II describes the gate’s ancilla state. (LLM, conf=0.93)

  cites Pittman et al., 2001 source

In the paper

“By combing the one-way model with linear optical quantum computing, recent theoretical proposals require much less resources and effectively replace the original KLM scheme”

What the sources say

• Partly supported

  The paper’s description of its approach (p. 1) says it combines cluster-state computation with KLM gates and is substantially simpler than the original KLM scheme; the Conclusion (p. 4) likewise calls it less demanding. It does not establish that the proposal effectively replaces KLM: it retains KLM components and presents an alternative scheme, not a replacement of KLM altogether. (LLM, conf=0.85)

  cites Nielsen, 2004 sourceExperimental — accuracy not yet measured
• Supported

  The Introduction (p. 1) describes a cluster-state approach to linear-optical quantum computation that moves away from KLM’s teleported gates. It estimates resource requirements many orders of magnitude lower than KLM’s, supporting the claim that the proposal offers a substantially more efficient alternative to the original scheme. (LLM, conf=0.86)

  cites Browne and Rudolph, 2005 source
• ?Not checked — no full text of the sourcecites Bodiya and Duan, 2006 source

In the paper

“It was recently shown that an efficient preparation of cluster states is possible with probabilistic two-qubit controlled phase flip gates (Duan and Raussendorf, 2005;Chen et al., 2006a).”

What the sources say

• Supported

  The paper states on p. 1 that it shows how to efficiently prepare 1D cluster states using probabilistic two-qubit controlled phase flip (CPF) gates, then construct 2D cluster states from those chains. Its summary on p. 4 says cluster states can be generated with efficient scaling in both qubit number and inverse gate-success probability. (LLM, conf=0.94)

  cites Duan and Raussendorf, 2005 source
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Chen et al., 2006a

In the paper

“Another significant step is the discovery of”

What the sources say

• ?Not checked — no full text of the sourcecites Raussendorf and Briegel, 2001 source
• Supported

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

  cites Raussendorf et al., 2003 source
• Supported

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

  cites Briegel et al., 2009 source

In the paper

“Furthermore, by introducing two linearoptical fusion operations, Browne and Rudolph (2005) achieved a greater degree of efficiency (∼ 10 2 ) and in a simpler scheme than the previous proposals.”

What the sources say

• Partly supported

  The Introduction (p. 1) introduces two fusion mechanisms, and the opening summary (p. 1) says the scheme is more efficient and simpler than previous proposals. The specific figure of approximately 10² is not supported: the Introduction (p. 1) estimates efficiency gains of several orders of magnitude over Nielsen’s proposal and many orders over KLM. (LLM, conf=0.83)

  cites Browne and Rudolph, 2005 sourceExperimental — accuracy not yet measured

In the paper

“Cluster states can be created by a controllable Ising-type interaction (Briegel and Raussendorf, 2001;Raussendorf and Briegel, 2001;Raussendorf et al., 2003).”

What the sources say

• Supported

  The paper describes cluster states generated under its interaction Hamiltonian (p. 3). It identifies that interaction as equivalent to an Ising model with time-dependent coupling (p. 1), and says the coupling can be switched on and off (p. 4). Together, these passages support creation by a controllable Ising-type interaction. (LLM, conf=0.94)

  cites Briegel and Raussendorf, 2001 source
• ?Not checked — no full text of the sourcecites Raussendorf and Briegel, 2001 source
• Supported

  In “Cluster states and their quantum correlations,” the paper describes creating a cluster state from a product state by applying an entangling transformation. It identifies the interaction Hamiltonian as Ising-form and says systems with a tunable Ising interaction are suitable when the coupling can be switched between zero and a nonzero value. (LLM, conf=0.94)

  cites Raussendorf et al., 2003 source

In the paper

“The resource overhead (Bell states, operations, etc.) for a reliable entangling gate in Nielsen's scheme is ∼ 10 3 , and thus about two orders of magnitude less than the original KLM protocol.”

What the sources say

• Partly supported

  On pp. 1 and 4, Nielsen estimates about 24 successful CZ₄/₉ operations per entangling gate, versus about 300 CZ₉/₁₆ operations and tens of thousands of optical elements for KLM. The p. 3 component counts make an overhead on the order of 10³ plausible, but the paper does not establish the claimed two-orders-of-magnitude reduction; its stated gate and element comparisons imply a smaller ratio. (LLM, conf=0.85)

  cites Nielsen, 2004 sourceExperimental — accuracy not yet measured

In the paper

“An even simpler set-up becomes possible with polarization encoding (Kiesel et al., 2005b;Langford et al., 2005;Okamoto et al., 2005) which in turn could be already applied, e.g., to observe cluster states for one-way quantum computing (see below, Kiesel et al., 2005a).”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Kiesel et al., 2005b
• Supported

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

  cites Langford et al., 2005 source
• Supported

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

  cites Okamoto et al., 2005 source

In the paper

“It requires stable interferometry over only the coherence length of the photons, i.e., the interferometer path lengths differences only need to be kept constant to within tens of microns, not fractions of a wavelength.”

What the sources say

• Supported

  The abstract (p. 1) says the scheme requires stable interferometry only over the photons’ coherence length. The Introduction (p. 1) contrasts this with wavelength-scale phase stability and gives an example coherence length of about 10⁻⁴ m, consistent with the cited tens-of-microns scale. (LLM, conf=0.91)

  cites Browne and Rudolph, 2005 source

In the paper

“Browne and Rudolph (2005) also showed that one can finally prepare a square-lattice cluster of N qubits with a temporal overhead scaling logarithmically with N , and with an operational overhead (i.e., number of fusion operations) scaling as ∼ N ln N (Chen et al., 2008).”

What the sources say

• Partly supported

  The Introduction (pp. 3–4) describes building two-dimensional clusters by fusion, supporting that part of the attribution. But the paper says it concentrates on a more compact layout rather than the square lattice (p. 2), and its resource calculation gives Bell pairs and fusion attempts per L-shaped unit (p. 4), not logarithmic temporal overhead or approximately N ln N fusion operations. (LLM, conf=0.88)

  cites Browne and Rudolph (2005) sourceExperimental — accuracy not yet measured
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Chen et al., 2008

In the paper

“It is notable that in these optical experiments during the computation genuine multi-particle entanglement and multi-path interference were observed, which did not appear in the previous implementations using nuclear magnetic resonance (Vandersypen et al. 2001).”

What the sources say

• Partly supported

  The description of the NMR experiment (p. 3) says its effective pure state remained separable under unitary transformations, supporting the absence of genuine multi-particle entanglement. The Fig. 1 caption (p. 12) describes interference in Shor’s algorithm, but our copy does not establish whether multi-path interference was observed in this NMR experiment or compare it with the optical experiments. (LLM, conf=0.83)

  cites Vandersypen et al. 2001 sourceExperimental — accuracy not yet measured

In the paper

“For photon loss alone, Ralph et al. (2005) and Varnava et al. (2006) and(2008) have designed loss-tolerant quantum computer schemes within the circuit-model and one-way model; the latter scheme can tolerate an overall optical loss, including source inefficiency and collection loss, up to an impressive 33%.”

What the sources say

• Supported

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

  cites Ralph et al. (2005) source
• Partly supported

  Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

  cites Varnava et al. (2006) sourceExperimental — accuracy not yet measured
• Supported

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

  cites Varnava et al. (2008) source

In the paper

“The majority of experimental demonstrations so far have relied on the SPDC photons, which suffers from undesired higherorder photon emission (Weinhold et al. 2008, this has been considered as the major source of error for most experiments reviewed here, see Section IV.D.1), large bandwidth, and the probabilistic manner of photon pair emission.”

What the sources say

• Supported

  The citation is attached to the higher-order photon-emission claim. The Error Model section (pp. 5–6) identifies higher-order photon terms from down-conversion as a major source of noise in photonic entangling gates and the leading error source in the quantum logic studied. The sentence’s reference to experiments reviewed by the citing authors is their own framing. (LLM, conf=0.91)

  cites Weinhold et al. 2008 source

In the paper

“Parametric down-conversion (Kwiat et al. 1995;White et al. 1999) has been serving as the main workhorse for the multiphoton experiments reviewed here; up to eight entangled photons have been observed (Yao et al. 2007a).”

What the sources say

• Partly supported

  Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

  cites Kwiat et al. 1995 sourceExperimental — accuracy not yet measured
• Supported

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

  cites White et al. 1999 source
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Yao et al. 2007a

In the paper

“Finally, it is worth mentioning that chip-scale waveguide quantum circuits have been created recently, and used to demonstrate high-visibility Hong-Ou-Mandel interference, CNOT gates, an instance of Shor's algorithm (Politi et al. 2008(Politi et al. , 2009)), and quantum walk (Peruzzo et al., 2010).”

What the sources say

• Partly supported

  The paper reports silica-on-silicon waveguide circuits and high-visibility two-photon interference (p. 2), as well as a CNOT gate (pp. 1, 3). It does not report an instance of Shor’s algorithm; the citing sentence also cites a separate 2009 paper for that claim. Quantum walk is attributed to Peruzzo et al. (2010), not to this source. (LLM, conf=0.88)

  cites Politi et al. 2008 sourceExperimental — accuracy not yet measured
• Supported

  The citation to Politi et al. (2009) is attached to the Shor’s-algorithm example, not the other demonstrations in the sentence. The paper reports a compiled version of Shor’s algorithm on an integrated waveguide silica-on-silicon chip (p. 1). (LLM, conf=0.94)

  cites Politi et al. 2009 source
• Supported

  The Peruzzo et al. citation is attached specifically to the quantum-walk demonstration, not to the preceding examples. The opening passage (p. 1) reports quantum walks of two photons in a 21-waveguide chip, and the device description (p. 2) identifies it as a compact silicon chip. (LLM, conf=0.94)

  cites Peruzzo et al., 2010 source

In the paper

“A similar technique, called quantum process tomography, has been used to fully characterize the quantum controlled-NOT gates (O'Brien et al. 2004).”

What the sources say

• Supported

  The Abstract states that the authors used quantum process tomography to completely characterize a two-qubit controlled-NOT gate. This directly supports the citing sentence’s description of the technique and its use. (LLM, conf=0.95)

  cites O'Brien et al. 2004 source

In the paper

“In contrast, for any single detector the count rate shows no interference at all.For example, p 1c = p 1c,2c (φ 1 , φ 2 ) + p 1c,2d (φ 1 , φ 2 ) = 1 2 , independent of φ 1 andφ 2 .”

In the paper

“If the two photons incident onto the PBS have identical polarization, then they will always go out along different directions, so there will be one photon in each of the two output modes.”

What the sources say

• ?Not checked — no full text of the sourcecites Pan and Zeilinger, 1998 source
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Pan et al., 2001b

In the paper

“Thus, if |β| = 1 (the photons â and b are fully distinguishable), this probability reads 1/2; if β = 0 (the photons are indistinguishable), it vanishes.”

In the paper

“A characteristic feature of the Hong-Ou-Mandel interference is that it is sensitive to path length changes on the order of the coherence length of the photons, while in a Mach-Zehnder interferometer one has a sub-wavelength sensitivity.”

In the paper

“The state |Ψ + can be distinguished from the other two by the fact that the emerging photons have different polarizations 20 .This results in a coincidence counts at detectors DH1 and DV1 or at DH2 and DV2.”

In the paper

“As in the case of the Hong-Ou-Mandel interferometer, the visibility of this polarization interference is reduced once the photons are partially distinguishable.E.g., by varying the relative optical paths before the photons reach the BS the overlap of the photon wave packets behind the beam splitter may be controlled, up to a total distinguishability.The full effect occurs for perfect overlap.”

In the paper

“states |Φ + and |Φ -both lead to a two-photon event at a single detector, and thus cannot be distinguished.”

In the paper

“For instance, Altepeter, Jeffrey, and Kwiat (2005) have reported an entangled photon pair source with an impressive count rate of over one million per second and a fidelity of 97.7%.”

What the sources say

• ?Not checked — no full text of the sourcecites Altepeter, Jeffrey, and Kwiat (2005) source

In the paper

“High dimensional entangled qudits have also been created by transverse spatial correlations of two SPDC photons (Neves et al., 2005), or using transverse momentum and position entanglement of photons emitted in SPDC, in a form called pixel entanglement (O'Sullivan-Hale et al., 2005).”

What the sources say

• ?Not checked — no full text of the sourcecites Neves et al., 2005 source
• ?Not checked — no full text of the sourcecites O'Sullivan-Hale et al., 2005 source

In the paper

“A short, ultraviolet pump pulse is sent first through an unbalanced Mach-Zehnder interferometer (the pump interferometer) creating two mutually coherent pump pulses α|short p + β|long p , and next through a BBO crystal.Then, if via SPDC a pump photon is converted into a pair, the latter is in the state α|short 1 |short 2 + β|long 1 |long 2 .(38)”

In the paper

“The polarization of each beam is completely undetermined, but the polarizations of the two beams are always anti-correlated.”

In the paper

“Nagata et al. have not only measured the reduced de Broglie wavelength of four-entangled photons, but also shown a visibility that exceeds the threshold to beat the standard quantum limit (see the original paper for details).”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Nagata et al.

In the paper

“After the interaction time t the resulting photon state is given by |ψ = e -itH0 |0 (Kok and Braunstein, 2000;Lamas-Linares et al., 2001;Simon and Bouwmeester, 2003), and in the number state representation reads |ψ = 1 cosh 2 τ ∞ n=0 √ n + 1 tanh n τ |ψ - n , |ψ - n = n m=0 (-1) m √ n + 1 |n -m, m; m, n -m .(42)”

What the sources say

• ?Not checked — no full text of the sourcecites Kok and Braunstein, 2000 source
• ?Not checked — no full text of the sourcecites Lamas-Linares et al., 2001 source
• ?Not checked — no full text of the sourcecites Simon and Bouwmeester, 2003 source

In the paper

“This is so only within a short interval of delay between the photons, while for path length differences larger than the coherence length of the detected photons the coherence between the two GHZ-terms vanishes.”

In the paper

“The probability per pulse to create a single pair in the desired modes was on the order of a few 10 -4 with a correspondingly smaller probability to create four photons and negligible for three pair events.”

In the paper

“The observers “Alice” and “Bob” were spatially separated by 400 m across the Innsbruck university science campus.”

In the paper

“However, as the two entangled ions were separated by approximately 3µm, the locality loophole was left widely open.”

In the paper

“Still the experiment had a detection efficiency well below the required minimum allowing to avoid the fair sampling assumption.”

In the paper

“Four-photon entanglement was later demonstrated by Pan et al., 2001a, andEibl et al., 2003), and used for a corresponding multi-photon falsification of local realism (see also Zhao et al. (2003a)).”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Pan et al., 2001a
• ?Not checked — no full text of the sourcecites Eibl et al., 2003 source
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Zhao et al. (2003a)

In the paper

“Hardy's scheme was later scaled up, so that (50 -h)% of photon pairs lead to coincidence events prohibited by local realism (where h is any small finite number).The effect was demonstrated in an experiment by Boschi et al. 1997.”

What the sources say

• ?Not checked — no full text of the sourcecites Boschi et al. 1997 source

In the paper

“Nevertheless, they are in conflict with quantum predictions as shown theoretically by Leggett (2003), and experimentally by Göblacher et all (2007).”

What the sources say

• ?Not checked — no full text of the sourcecites Leggett (2003) source
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Göblacher et all (2007)

In the paper

“At the same time measurements gave S Bell = 2.178 ± 0.0199, which violates the CHSH inequality by ∼9 standard deviations.”

What the sources say

• ?Not checked — no full text of the sourcecites Gröblacher et al. (2007) source

In the paper

“In section VI.E we discuss steps on the road toward satellite-based quantum communication and its first step, i.e., free-space distribution of entangled photon pairs over a distance of 10 km achieved in 2005 (Resch et al., 2005;Peng et al., 2005) and, more recently, over 144 km (Ursin et al., 2007;Fedrizzi et al., 2009).”

What the sources say

• ?Not checked — no full text of the sourcecites Resch et al., 2005 source
• ?Not checked — no full text of the sourcecites Peng et al., 2005 source
• ?Not checked — no full text of the sourcecites Ursin et al., 2007 source

In the paper

“With this ability, the dense coding protocol was implemented for all four Bell-states in the polarization degree-of-freedom, achieving an overall channel capacity of 1.18(3) bits per photon.”

What the sources say

• ?Not checked — no full text of the sourcecites Schuck et al. (2006) source

In the paper

“Barreiro et al. (2008) exploited pairs of photons simultaneously entangled in spin and orbital angular momentum and achieved a channel capacity of 1.630(6) bits, finally beating the channel capacity limit of 1.58 bits of the conventional linear-optics implementations.”

What the sources say

• ?Not checked — no full text of the sourcecites Barreiro et al. (2008) source

In the paper

“Thus three different messages could be operationally encoded by manipulating a single qubit only.53 Thus an increase of channel capacity to log 2 3 1.58 bits was possible-the highest value achievable using linear optics and classical communications, see Vaidman et al. (1999) andLutkenhaus et al. (1999).However, the observed signal-to-noise ratio reduced the actual channel capacity to on average 1.”

What the sources say

• ?Not checked — no full text of the sourcecites Mattle et al., 1996 source
• ?Not checked — no full text of the sourcecites Vaidman et al. (1999) source
• ?Not checked — no full text of the sourcecites Lutkenhaus et al. (1999) source

In the paper

“the actual success probability in the experiment (Pan et al. 2003b) was much lower as it relied on the SPDC to probabilistically create two pairs of entangled photons, thus only a small fraction of photons actually went through the purification system.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Pan et al. 2003b

In the paper

“The two-photon interference visibility of the original mixed states was 50% and 60%, respectively.In a single purification step it was increased to 84% and 88%.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Pan et al. (2003b)

In the paper

“In a second experiment entanglement purification was performed for a mixed state with F = 0.80.After purification, the observed entanglement fidelity for the sub-ensemble in the modes a3 and b3 was about 0.94 ± 0.01.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Pan et al. (2003b)

In the paper

“After a purification, S Bell = 2.29 ± 0.13 was measured.This violates the inequality by 2.2 standard deviations.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Walther et al. (2005a)

In the paper

“and of entangled photon pairs [over 600 m, see (Aspelmeyer et al., 2003a); over 7.8 km, see (Resch et al., 2005); over 13 km, see (Peng et al., 2005); and over 144 km, see (Ursin et al., 2007;Fedrizzi et al., 2009), see table I for a summary].”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Aspelmeyer et al., 2003a
• ?Not checked — no full text of the sourcecites Resch et al., 2005 source
• ?Not checked — no full text of the sourcecites Peng et al., 2005 source

In the paper

“More recently, a 144-km free-space link was built between two Canary Islands and used for distribution of one photon of an entangled pair (Ursin et al., 2007), and later, both photons (Fedrizzi et al., 2009).”

What the sources say

• ?Not checked — no full text of the sourcecites Ursin et al., 2007 source
• ?Not checked — no full text of the sourcecites Fedrizzi et al., 2009 source

In the paper

“So far, the majority of the reported multiphoton interferometry experiments face the problem of random arrivals of SPDC photon pairs.”

In the paper

“Long lifetimes for relevant coherences in such systems have been observed both in a room-temperature dilute atomic gas (Phillips et al., 2001), and in a sample of cold trapped atoms (Liu et al., 2001).”

What the sources say

• ?Not checked — no full text of the sourcecites Phillips et al., 2001 source
• ?Not checked — no full text of the sourcecites Liu et al., 2001 source

In the paper

“Recent experiments achieved single quantum excitation memory times of 1 ms using cold atomic ensembles (Zhao et al., 2009a), 6 ms using atomic rubidium confined in a one-dimensional optical lattice (Zhao et al., 2009b), and 0.1s using quantum memory confined in an optical lattice with laser compensation of the lattice light shifts (Radnaev et al. 2010).”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Zhao et al., 2009a
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Zhao et al., 2009b
• ?Not checked — no full text of the sourcecites Radnaev et al. 2010 source

In the paper

“These experiments are currently limited by the relatively short coherence time (∼ 20 µs ) of the memory qubits and the low conversion efficiency (∼ 15%) between photonic and atomic states.”

In the paper

“The KLM scheme subsequently spurred new experiments demonstrating probabilistic controlled two-photon gates.”

In the paper

“Laing et al. (2010) reported a two-photon quantum interference visibility of 99.5(4)%, a CNOT gate (the obtained average fidelity of logical basis was 96.9(2)%) and a path-entangled two-photon state (with fidelity of > 92%).”

What the sources say

• ?Not checked — no full text of the sourcecites Laing et al., 2010 source

In the paper

“The original proposal used dual-rail encoding and was first implemented by O'Brien et al., (2003).”

What the sources say

• ?Not checked — no full text of the sourcecites O'Brien et al., 2003 source

In the paper

“Very recently, Dousse et al. (2010) used carefully fabricated cavity to increase the collection efficiency, and created a source of polarization entangled photon pairs with a state fidelity of 0.67 and a rate of 0.12 per an excitation pulse.”

What the sources say

• ?Not checked — no full text of the sourcecites Dousse et al. (2010) source

In the paper

“For example, Mohseni et al. (2003) and Tame et al. (2007) demonstrated the two-qubit Deutsch-Josza algorithm in a circuit and a one-way model.”

What the sources say

• ?Not checked — no full text of the sourcecites Mohseni et al. (2003) source
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Tame et al. (2007)

In the paper

“Using the photonic graph states to simulate the creation and braiding of the anyons in the Kitaev model, a phase shift of π related to the anyon braiding was observed, confirming the predictions for the fractional statistics of Abelian 1/2 anyons (Lu et al. 2009;Pachos et al. 2009).”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Lu et al. 2009
• ?Not checked — no full text of the sourcecites Pachos et al. 2009 source

In the paper

“Recently, Lanyon et al. (2010) employed a photonic quantum computer to solve a quantum chemistry problem: calculation of the energies of the hydrogen molecule.In their experiment, the iterative phase estimation quantum algorithm was performed in full.With an assistance of a classical computer, it was possible to calculate the complete energy spectrum, up to 20 bits of precision.”

What the sources say

• ?Not checked — no full text of the sourcecites Lanyon et al. (2010) source

In the paper

“Using the cluster state |Φ c , a universal set of quantum logic operations, single-qubit rotations and non-trivial two-qubit gates were demonstrated (see Fig. 37).”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Walther et al., 2005

In the paper

“Following this proposal, in two experiments, Wagenknecht et al. (2010) and Barz et al. (2010), have demonstrated heralded generation of photon states, that are maximally entangled in polarization.”

What the sources say

• ?Not checked — no full text of the sourcecites Wagenknecht et al. (2010) source
• ?Not checked — no full text of the sourcecites Barz et al. (2010) source

In the paper

“In addition, Walther et al. also implemented a two-qubit Grover's quantum search algorithm using the box cluster |Φ 4 .The measured probability of the quantum computer to determine the correct outcome was about 90%.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Walther et al.

In the paper

“An improved experiment done by Prevedel et al. (2007b) incorporated active fast feed-forward, so that the earlier measurement outcomes could change the setting of a future measurement in real time.Particularly, the computational step (i.e., the individual feed-forward cycle) could be operated in less than 150 ns using electrooptical modulators.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Prevedel et al. (2007b)

In the paper

“A quantum dot can emit a single pair of entangled photons on demand, with a probability near close to one.However, it has a very low extraction efficiency.”

What the sources say

• ?Not checked — no full text of the sourcecites Stevenson et al. (2006) source

In the paper

“Ma et al. (2011) used polarization states of four photons to simulate a frustrated Heisenberg spin system: a spin-1/2 tetramer.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Ma et al. (2011)

In the paper

“A drawback of the experiment is that no feed-forward was used.This reduced the success rate of the computation by a factor of two, for every measurement.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Walther et al.

In the paper

“This was experimentally simulated using four photons from SPDC by Zhang et al., (2008a).”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Zhang et al., (2008a)

In the paper

“The Grover's search algorithm (Grover, 1997) has been realized by Kwiat et al. (2000) by designing an optical”

What the sources say

• ?Not checked — no full text of the sourcecites Kwiat et al. (2000) source

In the paper

“Decoherence-free subspaces, a type of passive error-preventing codes, have been experimentally realized using two photons by Kwiat et al. (2000) and four photons by Bourennane et al. (2004b).”

What the sources say

• ?Not checked — no full text of the sourcecites Kwiat et al. (2000) source
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Bourennane et al. (2004b)

In the paper

“Currently, mostly used room temperature silicon single-photon detectors can be operated at 10MHz with a peak efficiency of 65%, a dark count rate of about 100 Hz, and a timing jitter of typically 500ps; work is in progress to improve these parameters (see e.g.Kardyna et al., 2008).”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Kardyna et al., 2008

In the paper

“The latter proposal achieved a high error threshold of 0.75 × 10 -3 , the highest known for a local architecture.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Raussendorf et al. 2006;2007;Raussendorf and Harrington, 2007

In the paper

“Significant progress (Rosenberg et al., 2005;Lita, Miller and Nam, 2008;Divochiy et al., 2008) has been made on superconducting detectors capable of resolving photon-number, with an ultra low dark count rate (0.15 Hz at the wavelength of 1.3 µm), and high efficiency up to 95%.”

What the sources say

• ?Not checked — no full text of the sourcecites Rosenberg et al., 2005 source
• ?Not checked — no full text of the sourcecites Lita, Miller and Nam, 2008 source
• ?Not checked — no full text of the sourcecites Divochiy et al., 2008 source

In the paper

“Moreover, unfortunately, these loss-tolerant codes tend to amplify the depolarizing errors (e.g.bit flips and phase flips); the tradeoff has been discussed and new schemes have been designed which tolerates both errors in Rohde et al. (2007).”

What the sources say

• ?Not checked — no full text of the sourcecites Rohde et al. (2007) source

In the paper

“Furthermore, decoherence-free subspace approach was applied in an optical demonstration of the Deutsch-Jozsa algorithm (Mohseni et al., 2003), and for reliable measurementbased one-way information transfer (Prevedel et al., 2007a).”

What the sources say

• ?Not checked — no full text of the sourcecites Mohseni et al., 2003 source
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Prevedel et al., 2007a

In the paper

“Current silica waveguide circuits have dimensions of about one centimeter per logic gate.”

In the paper

“Gong et al. (2010) proposed a new scheme where the efficiency threshold for loss tolerance requires the product of source and detector efficiencies to be > 50%.”

What the sources say

• ?Not checked — no full text of the sourcecites Gong et al. (2010) source

In the paper

“To fight against the qubit-loss error, an especially serious problem for photonic qubits, Lu et al. (2008) demonstrated a four-qubit Grassl erasure correction code (for the theoretical proposals see Grassl (1997) and Ralph (2005)), and a tree-shaped graph state (Vanara et al. 2006).”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Lu et al. (2008)
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Grassl (1997)
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Ralph (2005)

In the paper

“Multi-photon interference reveals strictly non-classical phenomena.”

In the paper

“Cluster states up to six entangled photons have been realized (Walther et al., 2005b;Kiesel et al., 2005a;Lu et al., 2007), and applied to demonstrate elementary quantum gates and algorithms (Walther et al., 2005b).”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Walther et al., 2005b
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Kiesel et al., 2005a
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Lu et al., 2007

In the paper

“Thanks to this property, quantum key distribution with photons has now went long beyond first few-meter laboratory demonstrations, to free-space or fiber-based distributions over hundred kilometers (see e.g.Ursin et al, 2007;Rosenberg et at., 2007), and is rapidly commercialized into real life inter-city cryptographic networks.”

What the sources say

• ?Not checked — no full text of the sourcecites Ursin et al, 2007 source
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Rosenberg et at., 2007

In the paper

“The standard source of entangled photon pairs is nowadays the nonlinear optical process of spontaneous parametric down-conversion (SPDC; for a pioneering observation see Burnham and Weinberg, 1970), the inverse of frequency doubling and up-conversion.”

What the sources say

• ?Not checked — no full text of the sourcecites Burnham and Weinberg, 1970 source

In the paper

“Several ingredients of this scheme have been already demonstrated: entanglement swapping (Pan et al. 1998), purification (Pan et al. 2003), quantum memory (e.g., Yuan et al. 2008), etc.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Pan et al. 1998
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Pan et al. 2003
• ?Not checked — no full text of the sourcecites Yuan et al. 2008 source

In the paper

“Photons are the fastest information carriers, have a very weak coupling to the environment, and are thus best suited for quantum communication tasks.”

In the paper

“In quantum cryptography [Wiesner, 1983;Bennett and Brassard, 1984;Ekert, 1991; for a review see (Gisin et al., 2002)] complementary measurements on quantum systems are used to establish a secret key shared by two partners, thus enabling for the first time a provably secure communication.”

What the sources say

• ?Not checked — no full text of the sourcecites Wiesner, 1983 source
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Bennett and Brassard, 1984
• ?Not checked — no full text of the sourcecites Ekert, 1991 source

In the paper

“The joint property can be put as follows: the two spins, if measured with respect to the same direction, will be found opposite.”

In the paper

“The original idea of Peres was the observation that positivity of a partial transposition (PPT) of a density matrix (i.e. its transposition for just one subsystem) is a necessary condition for a state to be separable.”

What the sources say

• ?Not checked — no full text of the sourcecites Peres (1996) source

In the paper

“It is easy to show that the two reduced density matrices of Eq. ( 16) are endowed with the same spectrum.This does not hold for three or more particle subsystems.”

In the paper

“As soon as Alice measures the value of a spin projection along some axis, new information is gained, and for her the state of Bob's particle is a well defined pure one.This is independent of the spatial separation between them.”

In the paper

“Thus, if the phase relation between the two amplitudes is stable one can have absolutely noiseless interference with 100% visibility, while there is no single particle interference:”

In the paper

“All information contained in the state in Eq. ( 15) defines only joint properties (Schrödinger, 1935).”

What the sources say

• ?Not checked — no full text of the sourcecites Schrödinger, 1935 source

In the paper

“The state describes a coherent superposition of the two product states: there is no information in the whole Universe on which of the two possibilities will be detected at the measurement stage.”

In the paper

“Every pure state of two spins 1/2 can be put into the following form: cos α |↑ 1 |↑ 2 + sin α |↓ 1 |↓ 2 ,”

In the paper

“Entanglement can manifest itself in strictly quantum interference phenomena, that is, these phenomena can neither be explained by a classical wave nor by a classical particle picture.”

In the paper

“For any pure state, |Ψ , of a pair of subsystems, one described by a Hilbert space of dimension N , the other by a space of dimension M , say N ≤ M , one can find preferred bases, one for the first system, the other one for the second, such that the state is a sum of biorthogonal terms”

What the sources say

• ?Not checked — no full text of the sourcecites Peres (2002) source

In the paper

“Quantum d-level (high-dimensional) systems (”

What the sources say

• ?Not checked — no full text of the sourcecites Mair et al., 2001 source

In the paper

“With a similar method of triggering, Keller et al., (1998) used photons generated by two mutually coherent but timeseparated pulses from the same mode-locked laser (Keller et al., 1998).”

What the sources say

• ?Not checked — no full text of the sourcecites Keller et al., (1998) source
• ?Not checked — no full text of the sourcecites Keller et al., 1998 source

In the paper

“Weihs et al. (1996) realized an all-fiber three-path Mach-Zehnder interferometer, which is based on the idea of symmetric unbiased multiport BSs (Zeilinger et al., 1993).”

What the sources say

• ?Not checked — no full text of the sourcecites Weihs et al. (1996) source
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Zeilinger et al., 1993

In the paper

“The advantage of using polarization qubits stems from the fact that they can easily be created and manipulated with high precision by simple linear-optical elements such as polarizing beam splitters (PBS), polarizers and wave plates.”

In the paper

“The factor i in Eq. ( 28) is a consequence of unitarity.It describes a phase jump upon reflection (Zeilinger, 1981).”

What the sources say

• ?Not checked — no full text of the sourcecites Zeilinger, 1981 source

In the paper

“A disadvantage of using spatial qubits is that the coherence between |a and |b is sensitive to the relative phase between the paths a and b, and this is difficult to control in long-distance cases.”

In the paper

“an N -port interferometer was proposed by Reck et al. (1994), which can realize any U (N ) transformation for N optical spatial modes by using an arrangement of BS, phase shifters and mirrors.”

What the sources say

• ?Not checked — no full text of the sourcecites Reck et al. (1994) source

In the paper

“Photons, massless spin 1 particles, have only two eigenvalues of their spin along the direction of their propagation (wave vector), ± .These two spin values correspond to righthanded and left-handed circular polarization.”

In the paper

“However, similar interference effects can be observed using any of the photon's degrees of freedom, e.g.polarization.”

In the paper

“For instance, two single photons successively emitted from a single quantum dot were overlapped on a BS and the Hong-Ou-Mandel effect was observed (Santori et al. 2002).”

What the sources say

• ?Not checked — no full text of the sourcecites Santori et al. 2002 source

In the paper

“Actually, an n-particle interferometer generalized along the above reasoning will only exhibit nparticle fringes, but no (n-1)-, (n-2)-,..., single-particle fringes (Greenberger et al., 1990).”

What the sources say

• ?Not checked — no full text of the sourcecites Greenberger et al., 1990 source

In the paper

“The two photons exit the BS paired via only one (random) output port.This is a bunching effect due to the bosonic character of photons.”

In the paper

“The original Hong-Ou-Mandel experiment used the two photons of the same signal-idler pair from parametric down-conversion (see Section IV.A).”

What the sources say

• ?Not checked — no full text of the sourcecites Hong, Ou and Mandel, 1987 source

In the paper

“As we shall see in the following chapters, such entangled states serve as a central physical resource in various quantum information protocols like quantum cryptography, quantum teleportation, entanglement swapping and in tests aimed at excluding hidden variable models of quantum mechanics.”

In the paper

“The photon's coherence length can range from a few hundred micrometers, in pulsed parametric down-conversion, to a few meters for trapped ions.”

In the paper

“In fact, the state |Ψ - can be encoded with any degree of freedom (e.g., color encoding, see Moehring et al. 2007) and can be pinpointed by a two-channel coincidence behind a BS.”

What the sources say

• ?Not checked — no full text of the sourcecites Moehring et al. 2007 source

In the paper

“As a PBS customarily transmits H and reflects V polarization, a coincidence detection between the two outputs can originate only if either both photons are transmitted (resulting in a |HH case) or both are reflected (|V V case).The two cases are quantum mechanically indistinguishable, if the photons are indistinguishable.Thus again, an entangled state |φ - cd can be generated using postselection.”