| 1. |
- Abidin, Aysajan, et al.
(author)
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Vulnerability of "A Novel Protocol-Authentication Algorithm Ruling out a Man-in-the-Middle Attack in Quantum Cryptography"
- 2009
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In: International Journal of Quantum Information. - 0219-7499. ; 7:5, s. 1047-1052
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Journal article (peer-reviewed)abstract
- In this paper, we review and comment on "A novel protocol-authentication algorithm ruling out a man-in-the-middle attack in quantum cryptography" [M. Peev et al., Int. J. Quant. Inf. 3 (2005) 225]. In particular, we point out that the proposed primitive is not secure when used in a generic protocol, and needs additional authenticating properties of the surrounding quantum-cryptographic protocol.
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| 2. |
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| 3. |
- Durt, Thomas, et al.
(author)
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On Mutually Unbiased Bases
- 2010
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In: International journal of quantum information. - 0219-7499. ; 8:4, s. 535-640
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Research review (peer-reviewed)abstract
- Mutually unbiased bases for quantum degrees of freedom are central to all theoretical investigations and practical exploitations of complementary properties. Much is known about mutually unbiased bases, but there are also a fair number of important questions that have not been answered in full as yet. In particular, one can find maximal sets of N + 1 mutually unbiased bases in Hilbert spaces of prime-power dimension N = p(M), with p prime and m a positive integer, and there is a continuum of mutually unbiased bases for a continuous degree of freedom, such as motion along a line. But not a single example of a maximal set is known if the dimension is another composite number (N = 6; 10; 12,...). In this review, we present a unified approach in which the basis states are labeled by numbers 0, 1, 2,..., N - 1 that are both elements of a Galois field and ordinary integers. This dual nature permits a compact systematic construction of maximal sets of mutually unbiased bases when they are known to exist but throws no light on the open existence problem in other cases. We show how to use the thus constructed mutually unbiased bases in quantum-informatics applications, including dense coding, teleportation, entanglement swapping, covariant cloning, and state tomography, all of which rely on an explicit set of maximally entangled states (generalizations of the familiar two-q-bit Bell states) that are related to the mutually unbiased bases. There is a link to the mathematics of finite affine planes. We also exploit the one-to-one correspondence between unbiased bases and the complex Hadamard matrices that turn the bases into each other. The ultimate hope, not yet fulfilled, is that open questions about mutually unbiased bases can be related to open questions about Hadamard matrices or affine planes, in particular the notorious existence problem for dimensions that are not a power of a prime. The Hadamard-matrix approach is instrumental in the very recent advance, surveyed here, of our understanding of the N-6 situation. All evidence indicates that a maximal set of seven mutually unbiased bases does not exist - one can find no more than three pairwise unbiased bases - although there is currently no clear-cut demonstration of the case.
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| 4. |
- Heydari, Hoshang
(author)
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Different classes of quantum gates entanglers
- 2009
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In: International journal of quantum information. - : World scientific publishing company. - 0219-7499. ; 7:1, s. 279-285
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Journal article (peer-reviewed)abstract
- We construct quantum gates entanglers for different classes of multipartite states. In particular, we construct entangler operators for W and GHZ classes of multipartite states based on the construction of the concurrence classes. We also discuss in detail these two classes of the quantum gates entanglers for three-partite states.
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| 5. |
- Heydari, Hoshang
(author)
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Generalized controlled phase quantum gates entanglers
- 2009
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In: International journal of quantum information. - : World scientific publishing. - 0219-7499. ; 7:6, s. 1211-1216
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Journal article (peer-reviewed)abstract
- We construct a generalized controlled phased gate entangler for a multi-qubit state based on the geometrical structure of quantum systems. We also investigate the relation between the generalized controlled phase construction of a quantum gate entangler and graph state for two-qubit and three-qubit states.
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| 6. |
- Khrennikov, Andrei, 1958-
(author)
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Buonomano against Bell : Nonergodicity or nonlocality?
- 2017
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In: International Journal of Quantum Information. - : World Scientific. - 0219-7499 .- 1793-6918. ; 15:8
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Journal article (peer-reviewed)abstract
- The aim of this note is to attract attention of the quantum foundational community to the fact that in Bell's arguments, one cannot distinguish two hypotheses: (a) quantum mechanics is nonlocal, (b) quantum mechanics is nonergodic. Therefore, experimental violations of Bell's inequality can be as well interpreted as supporting the hypothesis that stochastic processes induced by quantum measurements are nonergodic. The latter hypothesis was discussed actively by Buonomano since 1980. However, in contrast to Bell's hypothesis on nonlocality, it did not attract so much attention. The only experiment testing the hypothesis on nonergodicity was performed in neutron interferometry (by Summhammer, in 1989). This experiment can be considered as rejecting this hypothesis. However, it cannot be considered as a decisive experiment. New experiments are badly needed. We point out that a nonergodic model can be realistic, i.e. the distribution of hidden (locall) variables is well-defined. We also discuss coupling of violation of the Bell inequality with violation of the condition of weak mixing for ergodic dynamical systems.
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| 7. |
- Khrennikov, Andrei
(author)
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Emerging quantum mechanics : Coefficient of second-order coherence from classical random fields interacting with threshold type detectors
- 2014
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In: International Journal of Quantum Information. - : World Scientific. - 0219-7499 .- 1793-6918. ; 12:07n08
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Journal article (peer-reviewed)abstract
- This paper is a contribution to the project "emergent quantum mechanics" unifying a variety of attempts to treat quantum mechanics (QMs) as emergent from other theories pretending on finer descriptions of quantum phenomena. More concretely it is about an attempt to model detection probabilities predicted by QM for single photon states by using classical random fields interacting with detectors of the threshold type. Continuous field model, prequantum classical statistical field theory (PCSFT), was developed in recent years and its predictions about probabilities and correlations match well with QM. The main problem is to develop the corresponding measurement theory which would describe the transition from continuous fields to discrete events, "clicks of detectors". Some success was achieved and the click-probabilities for quantum observables can be derived from PCSFT by modeling interaction of fields with the threshold type detectors. However, already for the coefficient of second-order coherence g(2) (0) calculations are too complicated and only an estimation of g(2)(0) obtained. In this paper, we present results of numerical simulation based on PCSFT and modeling of interaction with threshold type detectors. The "prequantum random field" interacting with a detector is modeled as the Brownian motion in the space of classical fields (Wiener process in complex Hilbert space). Simulation for g(2)(0) shows that this coefficient approaches zero with increase of the number of detections.
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| 8. |
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| 9. |
- Khrennikov, Andrei, et al.
(author)
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On an experimental test of prequantum theory of classical random fields : an estimate from above of the coefficient of second-order coherence
- 2012
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In: International Journal of Quantum Information. - 0219-7499. ; 10:8, s. Article ID: 1241014-
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Journal article (peer-reviewed)abstract
- We show that quantum probabilities for photon detection can be reproduced by a model in which classical random fields interact with detectors of the threshold type. This approach is applied to the old problem of distinguishing classical and quantum light sources with the aid of the coefficient of second-order coherence g(2) (0) ( the problem of "existence of photon"). In our classical random field model, we obtain an estimate of this coefficient implying that it becomes strictly less than one for sufficiently small value of parameter is an element of = (epsilon) over bar/epsilon(d), where (epsilon) over bar (pulse) is the average energy of pulses (photons) emitted by a source and epsilon(d) is the detection threshold. This prediction can in principle be tested experimentally. Thus in the presented model experimental technicalities (such as e. g. the detection thresholds) are lifted to the level of the fundamental entities of theory.
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| 10. |
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