Authors:Carlos Ortega Laurel, Shi-Hai Dong, M. Cruz-Irisson Abstract: International Journal of Quantum Information, Ahead of Print. This paper presents a steganographical algorithm based on least significant bit (LSB) from the most significant bit information (MSBI) and the equivalence of a bit pixel image to a quantum pixel image, which permits to make the information communicate secretly onto quantum pixel images for its secure transmission through insecure channels. This algorithm offers higher security since it exploits the Shannon entropy for an image. Citation: International Journal of Quantum Information PubDate: 2016-07-15T07:15:06Z DOI: 10.1142/S0219749916500210

Authors:Qingyong Wang, Yangyang Du, Chunfeng Wu, Gangcheng Wang, Chunfang Sun, Kang Xue Abstract: International Journal of Quantum Information, Ahead of Print. In this paper, it is shown that the Hamiltonian of the open spin-1 XXZ chain model can be constructed from the generators of the Birman–Murakami–Wenzl (B–M–W) algebra. Without the topological parameter d (describing the unknotted loop [math] in topology) reducing to a fixed value, the topological basis states can be connected with the open XXZ spin chain. Then some particular properties of the topological basis states in this system have been investigated. We find that the topological basis states are the three eigenstates of a four-spin-1 XXZ chain model without boundary term. Specifically, all the spin single states of the system fall on the topological basis subspace. And the number of the spin single states of the system is equal to that of the topological basis states. Citation: International Journal of Quantum Information PubDate: 2016-07-07T06:24:00Z DOI: 10.1142/S0219749916500180

Authors:Majid Haghparast, Ali Bolhassani Abstract: International Journal of Quantum Information, Ahead of Print. Reversible logic is one of the indispensable aspects of emerging technologies for reducing physical entropy gain, since reversible circuits do not lose information in the form of internal heat during computation. This paper aimed to initiate constructing parity preserving reversible circuits. A novel parity preserving reversible block, HB is presented. Then a new design of a cost-effective parity preserving reversible full adder/subtractor (PPFA/S) is proposed. Next, we suggested a new parity preserving binary to BCD converter. Finally, we proposed new realization of parity preserving reversible BCD adder. The proposed designs are cost-effective in terms of quantum cost and delay. All the scales are in the NANO-metric area. Citation: International Journal of Quantum Information PubDate: 2016-07-07T05:40:09Z DOI: 10.1142/S0219749916500192

Authors:Jaideep Mulherkar Abstract: International Journal of Quantum Information, Ahead of Print. We study the classical and entanglement-assisted capacity of a forgetful quantum memory channel that randomly switches between two qubit depolarizing channels. We show that when the input consists of two qubits then depending on channel parameters either the maximally entangled input states or product input states achieve the two-use classical capacity. We conjecture that as the number of input qubits is increased the classical capacity approaches the product state capacity for all values of the parameters. We also derive an expression for the entanglement-assisted classical capacity of this quantum memory channel in terms of the entropy rate of a Markov chain. Citation: International Journal of Quantum Information PubDate: 2016-06-24T02:48:07Z DOI: 10.1142/S0219749916500179

Authors:Ya-Li Yuan, Xi-Wen Hou Abstract: International Journal of Quantum Information, Ahead of Print. The investigation of quantum discord has mostly focused on two-qubit systems due to the complicated minimization involved in quantum discord for high-dimensional states. In this work, three geometric discords are studied for the thermal state in a two-qutrit system with various couplings, external magnetic fields, and temperatures as well, where the entanglement measured in terms of the generalized negativity is calculated for reference. It is shown that three geometric discords are more robust against temperature and magnetic field than the entanglement negativity. However, all four quantities exhibit a similar behavior at lower temperature and weak magnetic field. Remarkably, three geometric discords at finite temperature reveal the phenomenon of double sudden changes at different magnetic fields while the negativity does not. Moreover, the hierarchy among three discords is discussed. Those adjustable discords with the varied coupling, temperature, and magnetic field are useful for the understanding of quantum correlations in high-dimensional states and quantum information processing. Citation: International Journal of Quantum Information PubDate: 2016-06-17T03:19:50Z DOI: 10.1142/S0219749916500167

Authors:Na Chen, Dong-Xiao Quan, Chang-Hua Zhu, Jia-Zhen Li, Chang-Xing Pei Abstract: International Journal of Quantum Information, Ahead of Print. In this paper, we propose a scheme for deterministic joint remote state preparation (JRSP). Two spatially separated senders intend to help a receiver remotely prepare an arbitrary single-qubit state. Four-particle partially entangled state is constructed to serve as the quantum channel. By determining right unitary operations for the senders and appropriate recovery operations for the receiver, the target state can be reestablished with unit success probability, irrespective of the channel parameter. Citation: International Journal of Quantum Information PubDate: 2016-06-15T09:44:53Z DOI: 10.1142/S0219749916500155

Abstract: International Journal of Quantum Information, Ahead of Print. The transition time between states plays an important role in designing quantum devices as they are very sensitive to environmental influences. Decoherence phenomenon is responsible for possible destructions of the entanglement that is a fundamental requirement to implement quantum information processing systems. If the time between states is minimized, the decoherence effects can be reduced, thus, it is advantageous to the designer to develop expressions for time performance measures. Quantum speed limit (QSL) problem has been studied from the theoretical point of view, providing general results. Considering the implementation of quantum control systems, as the decoherence phenomenon is unavoidable, it is important to apply these general results to particular cases, developing expressions and performance measures, to assist control engineering designers. Here, a minimum time performance measure is defined for quantum control problems, for time-independent or time-dependent Hamiltonians, and applied to some practical examples, providing hints that may be useful for researchers pursuing optimization strategies for quantum control systems. Citation: International Journal of Quantum Information PubDate: 2016-06-14T08:51:04Z DOI: 10.1142/S0219749916500143

Authors:T. Kaufherr Abstract: International Journal of Quantum Information, Ahead of Print. The gauge invariant nonlocal quantum dynamics that is responsible for the Aharonov–Bohm (AB) effect is described. It is shown that it may be verified experimentally. Citation: International Journal of Quantum Information PubDate: 2016-06-10T08:57:58Z DOI: 10.1142/S021974991640013X

Authors:Maria Luisa Dalla Chiara, Roberto Giuntini, Giuseppe Sergioli, Roberto Leporini Abstract: International Journal of Quantum Information, Ahead of Print. Classical and quantum parallelism are deeply different, although it is sometimes claimed that quantum Turing machines are nothing but special examples of classical probabilistic machines. We introduce the concepts of deterministic state machine, classical probabilistic state machine and quantum state machine. On this basis, we discuss the question: To what extent can quantum state machines be simulated by classical probabilistic state machines? Each state machine is devoted to a single task determined by its program. Real computers, however, behave differently, being able to solve different kinds of problems. This capacity can be modeled, in the quantum case, by the mathematical notion of abstract quantum computing machine, whose different programs determine different quantum state machines. The computations of abstract quantum computing machines can be linguistically described by the formulas of a particular form of quantum logic, termed quantum computational logic. Citation: International Journal of Quantum Information PubDate: 2016-06-08T10:31:51Z DOI: 10.1142/S0219749916400190

Authors:Carlo Cafaro, Sean Alan Ali, Adom Giffin Abstract: International Journal of Quantum Information, Ahead of Print. We present an explicit reexamination of Gisin’s 1991 original proof concerning the violation of Bell’s inequality for any pure entangled state of two-particle systems. Given the relevance of Gisin’s work, our analysis is motivated by pedagogical reasons and allows the straightening of a few mathematical points in the original proof that in no way change the physical conclusions reached by Gisin. Citation: International Journal of Quantum Information PubDate: 2016-06-08T10:29:15Z DOI: 10.1142/S0219749916300035

Abstract: International Journal of Quantum Information, Ahead of Print. We investigate the internal-state Bell nonlocal entanglement dynamics, as measured by CHSH inequality of two atoms interacting with a vacuum multi-mode noise field by taking into account the spatial degrees of freedom of the two atoms. The dynamics of Bell nonlocality of the atoms with the atomic internal states being initially in a Werner-type state is studied, by deriving the analytical solutions of the Schrödinger equation, and tracing over the degrees of freedom of the field and the external motion of the two atoms. In addition, through comparison with entanglement as measured by concurrence, we find that the survival time of entanglement is much longer than that of the Bell-inequality violation. And the comparison of the quantum correlation time between two Werner-type states is discussed. Citation: International Journal of Quantum Information PubDate: 2016-06-08T10:29:13Z DOI: 10.1142/S0219749916500118

Authors:Andrei Khrennikov Abstract: International Journal of Quantum Information, Ahead of Print. Recent tremendous development of quantum information theory has led to a number of quantum technological projects, e.g. quantum random generators. This development had stimulated a new wave of interest in quantum foundations. One of the most intriguing problems of quantum foundations is the elaboration of a consistent and commonly accepted interpretation of a quantum state. Closely related problem is the clarification of the notion of quantum randomness and its interrelation with classical randomness. In this short review, we shall discuss basics of classical theory of randomness (which by itself is very complex and characterized by diversity of approaches) and compare it with irreducible quantum randomness. We also discuss briefly “digital philosophy”, its role in physics (classical and quantum) and its coupling to the information interpretation of quantum mechanics (QM). Citation: International Journal of Quantum Information PubDate: 2016-05-27T02:56:09Z DOI: 10.1142/S0219749916400098

Authors:Florin Moldoveanu Abstract: International Journal of Quantum Information, Ahead of Print. Recent quantum reconstruction projects demand pure unitary time evolution which seems to contradict the collapse postulate. Inspired by Zurek’s environment assisted invariance idea, a natural unitary realization of wave function collapse is proposed using Grothendieck group construction for the tensor product commutative monoid. Citation: International Journal of Quantum Information PubDate: 2016-05-24T03:41:56Z DOI: 10.1142/S0219749916400153

Authors:Habib Ouerdiane Abstract: International Journal of Quantum Information, Ahead of Print. We study an evolution equation associated with the integer power of the Gross Laplacian [math] and a potential function V on an infinite-dimensional space. The initial condition is a generalized function. The main technique we use is the representation of the Gross Laplacian as a convolution operator. This representation enables us to apply the convolution calculus on a suitable distribution space to obtain the explicit solution of the perturbed evolution equation. Our results generalize those previously obtained by Hochberg [K. J. Hochberg, Ann. Probab. 6 (1978) 433.] in the one-dimensional case with [math], as well as by Barhoumi–Kuo–Ouerdiane for the case [math] (See Ref. [A. Barhoumi, H. H. Kuo and H. Ouerdiane, Soochow J. Math. 32 (2006) 113.]). Citation: International Journal of Quantum Information PubDate: 2016-05-24T03:41:54Z DOI: 10.1142/S0219749916400189

Authors:L. Vaidman Abstract: International Journal of Quantum Information, Ahead of Print. The counterfactuality of recently proposed protocols is analyzed. A definition of “counterfactuality” is offered and it is argued that an interaction-free measurement (IFM) of the presence of an opaque object can be named “counterfactual”, while proposed “counterfactual” measurements of the absence of such objects are not counterfactual. The quantum key distribution protocols which rely only on measurements of the presence of the object are counterfactual, but quantum direct communication protocols are not. Therefore, the name “counterfactual” is not appropriate for recent “counterfactual” protocols which transfer quantum states by quantum direct communication. Citation: International Journal of Quantum Information PubDate: 2016-05-20T09:38:14Z DOI: 10.1142/S0219749916400128

Authors:Stephan Sponar Abstract: International Journal of Quantum Information, Ahead of Print. Heisenberg’s uncertainty principle in a formulation of uncertainties, intrinsic to any quantum system, is rigorously proven and demonstrated in various quantum systems. Nevertheless, Heisenberg’s original formulation of the uncertainty principle was given in terms of a reciprocal relation between the error of a position measurement and the thereby induced disturbance on a subsequent momentum measurement. However, a naive generalization of a Heisenberg-type error-disturbance relation for arbitrary observables is not valid. An alternative universally valid relation was derived by Ozawa in 2003. Though universally valid, Ozawa’s relation is not optimal. Recently, Branciard has derived a tight error-disturbance uncertainty relation (EDUR), describing the optimal trade-off between error and disturbance under certain conditions. Here, we report a neutron-optical experiment that records the error of a spin-component measurement, as well as the disturbance caused on another spin-component to test EDURs. We demonstrate that Heisenberg’s original EDUR is violated, and Ozawa’s and Branciard’s EDURs are valid in a wide range of experimental parameters, as well as the tightness of Branciard’s relation. Citation: International Journal of Quantum Information PubDate: 2016-05-20T09:38:13Z DOI: 10.1142/S0219749916400165

Abstract: International Journal of Quantum Information, Ahead of Print. By performing X-rays measurements in the underground laboratory of Gran Sasso, LNGS-INFN, we test a basic principle of quantum mechanics: the Pauli exclusion principle (PEP). In the future, we aim to use a similar experimental technique to search for X-rays as a signature of the spontaneous collapse of the wave function predicted by continuous spontaneous localization theories. We present the achieved results of the VIP experiment and the future plans to gain two orders of magnitude in testing PEP with the recently VIP2 setup installed at Gran Sasso. Citation: International Journal of Quantum Information PubDate: 2016-05-19T11:35:04Z DOI: 10.1142/S0219749916400177

Authors:Elena R. Loubenets Abstract: International Journal of Quantum Information, Ahead of Print. We specify the local quasi hidden variable (LqHV) model reproducing the probabilistic description of all N-partite joint von Neumann measurements on an N-qudit state. Via this local probability model, we derive a new upper bound on the maximal violation by an N-qudit state of Bell inequalities of any type (either on correlation functions or on joint probabilities) for S observables per site. This new upper bound not only improves for all [math] S and d the corresponding results available for general Bell inequalities in the literature but also, for the N-qubit case with two observables per site, reduces exactly to the attainable upper bound known for quantum violations of correlation [math] setting Bell inequalities in a dichotomic case. Citation: International Journal of Quantum Information PubDate: 2016-05-19T11:35:03Z DOI: 10.1142/S0219749916400104

Authors:G. Adenier, D. Calonico, S. Micalizio, N. Samantaray, I. P. Degiovanni, I. Ruo Berchera Abstract: International Journal of Quantum Information, Ahead of Print. Four-wave mixing (4WM) is a known source of intense non-classical twin beams. It can be generated when an intense laser beam (the pump) and a weak laser beam (the seed) overlap in a [math] medium (here Cesium vapor), with frequencies close to resonance with atomic transitions. The twin beams generated by 4WM have frequencies naturally close to atomic transitions, and can be intense (gain [math]) even in the CW pump regime, which is not the case for PDC [math] phenomenon in nonlinear crystals. So, 4WM is well suited for atom-light interaction and atom-based quantum-protocols. Here, we present the first realization of a source of 4-wave mixing exploiting [math] line of Cesium atoms. Citation: International Journal of Quantum Information PubDate: 2016-05-19T03:27:06Z DOI: 10.1142/S0219749916400141

Abstract: International Journal of Quantum Information, Ahead of Print. We propose an adynamical interpretation of quantum theory called Relational Blockworld (RBW) where the fundamental ontological element is a 4D graphical amalgam of space, time and sources called a “spacetimesource element.” These are fundamental elements of space, time and sources, not source elements in space and time. The transition amplitude for a spacetimesource element is computed using a path integral with discrete graphical action. The action for a spacetimesource element is constructed from a difference matrix K and source vector J on the graph, as in lattice gauge theory. K is constructed from graphical field gradients so that it contains a non-trivial null space and J is then restricted to the row space of K, so that it is divergence-free and represents a conserved exchange of energy–momentum. This construct of K and J represents an adynamical global constraint between sources, the spacetime metric and the energy–momentum content of the spacetimesource element, rather than a dynamical law for time-evolved entities. To illustrate this interpretation, we explain the simple EPR-Bell and twin-slit experiments. This interpretation of quantum mechanics constitutes a realist, psi-epistemic model that might underwrite certain information-theoretic accounts of the quantum. Citation: International Journal of Quantum Information PubDate: 2016-05-13T06:45:32Z DOI: 10.1142/S0219749916400074

Authors:Satoshi Iriyama, Masanori Ohya Abstract: International Journal of Quantum Information, Ahead of Print. The adaptive dynamics is known as a new mathematics to treat with a complex phenomena, for example, chaos, quantum algorithm and psychological phenomena. In this paper, we briefly review the notion of the adaptive dynamics, and explain the definition of the generalized Turing machine (GTM) and recognition process represented by the Fock space. Moreover, we show that there exists the quantum channel which is described by the GKSL master equation to achieve the Chaos Amplifier used in [M. Ohya and I. V. Volovich, J. Opt. B 5(6) (2003) 639., M. Ohya and I. V. Volovich, Rep. Math. Phys. 52(1) (2003) 25.] Citation: International Journal of Quantum Information PubDate: 2016-05-13T06:45:28Z DOI: 10.1142/S0219749916400086

Authors:M. Kupczynski Abstract: International Journal of Quantum Information, Ahead of Print. Entangled physical systems are an important resource in quantum information. Many papers were published trying to grasp the meaning of entanglement. It was noticed that a Hilbert space of possible state vectors of compound physical system can be partitioned by introducing various tensor product structures induced by the experimentally accessible observables (interactions and measurements). In this sense, the entanglement is relative to a particular set of experimental capabilities. Inspired by these results some authors claim that in fact all quantum states are entangled. In this paper, we show that this claim is incorrect and we discuss in operational way differences existing between separable and entangled states. A sufficient condition for entanglement is the violation of Bell–CHSH-CH inequalities and/or steering inequalities. Since there exist experiments outside the domain of quantum physics violating these inequalities therefore in the operational approach one cannot say that the entanglement is an exclusive quantum phenomenon. We also explain that an unambiguous experimental certification of the entanglement is a difficult task because classical statistical significance tests may not be trusted if sample homogeneity cannot be tested or is not tested carefully enough. Citation: International Journal of Quantum Information PubDate: 2016-05-11T11:15:48Z DOI: 10.1142/S0219749916400037

Authors:Hans-Thomas Elze Abstract: International Journal of Quantum Information, Ahead of Print. Cellular automata (CA) can show well known features of quantum mechanics (QM), such as a linear updating rule that resembles a discretized form of the Schrödinger equation together with its conservation laws. Surprisingly, a whole class of “natural” Hamiltonian CA, which are based entirely on integer-valued variables and couplings and derived from an action principle, can be mapped reversibly to continuum models with the help of sampling theory. This results in “deformed” quantum mechanical models with a finite discreteness scale l, which for [math] reproduce the familiar continuum limit. Presently, we show, in particular, how such automata can form “multipartite” systems consistently with the tensor product structures of non-relativistic many-body QM, while maintaining the linearity of dynamics. Consequently, the superposition principle is fully operative already on the level of these primordial discrete deterministic automata, including the essential quantum effects of interference and entanglement. Citation: International Journal of Quantum Information PubDate: 2016-05-11T11:15:45Z DOI: 10.1142/S0219749916400013

Authors:Francesco De Martini, Enrico Santamato Abstract: International Journal of Quantum Information, Ahead of Print. The traditional standard theory of quantum mechanics is unable to solve the spin-statistics problem, i.e. to justify the utterly important “Pauli Exclusion Principle” but by the adoption of the complex standard relativistic quantum field theory. In a recent paper [E. Santamato and F. D. De Martini, Found. Phys. 45 (2015) 858] we presented a complete proof of the spin-statistics problem in the nonrelativistic approximation on the basis of the “Conformal Quantum Geometrodynamics” (CQG). In this paper, by the same theory, the proof of the spin-statistics theorem (SST) is extended to the relativistic domain in the scenario of curved spacetime. No relativistic quantum field operators are used in the present proof and the particle exchange properties are drawn from rotational invariance rather than from Lorentz invariance. Our relativistic approach allows to formulate a manifestly step-by-step Weyl gauge invariant theory and to emphasize some fundamental aspects of group theory in the demonstration. As in the nonrelativistic case, we find once more that the “intrinsic helicity” of the elementary particles enters naturally into play. It is therefore this property, not considered in the standard quantum mechanics (SQM), which determines the correct spin-statistics connection observed in Nature. Citation: International Journal of Quantum Information PubDate: 2016-04-28T07:45:44Z DOI: 10.1142/S0219749916400116

Authors:Noboru Watanabe Abstract: International Journal of Quantum Information, Ahead of Print. We review some notions for quantum dynamical entropies. The dynamical entropy of quantum systems is discussed and a numerical computation of the dynamical entropy is carried for the open system dynamics. Citation: International Journal of Quantum Information PubDate: 2016-04-28T07:45:36Z DOI: 10.1142/S0219749916400050

Authors:Brian R. La Cour, Corey I. Ostrove, Granville E. Ott, Michael J. Starkey, Gary R. Wilson Abstract: International Journal of Quantum Information, Ahead of Print. This paper describes a novel approach to emulate a universal quantum computer with a wholly classical system, one that uses a signal of bounded duration and amplitude to represent an arbitrary quantum state. The signal may be of any modality (e.g. acoustic, electromagnetic, etc.) but this paper will focus on electronic signals. Individual qubits are represented by in-phase and quadrature sinusoidal signals, while unitary gate operations are performed using simple analog electronic circuit devices. In this manner, the Hilbert space structure of a multi-qubit quantum state, as well as a universal set of gate operations, may be fully emulated classically. Results from a programmable prototype system are presented and discussed. Citation: International Journal of Quantum Information PubDate: 2016-04-07T08:50:53Z DOI: 10.1142/S0219749916400049

Abstract: International Journal of Quantum Information, Ahead of Print. We discuss the recently observed “loophole free” violation of Bell’s inequalities in the framework of a physically realist view of quantum mechanics (QM), which requires that physical properties are attributed jointly to a system, and to the context in which it is embedded. This approach is clearly different from classical realism, but it does define a meaningful “quantum realism” from a general philosophical point of view. Consistently with Bell test experiments, this quantum realism embeds some form of non-locality, but does not contain any action at a distance, in agreement with QM. Citation: International Journal of Quantum Information PubDate: 2016-04-07T08:50:52Z DOI: 10.1142/S0219749916400025

Authors:S. A. Rashkovskiy Abstract: International Journal of Quantum Information, Ahead of Print. It is shown that the Schrödinger equation can be written in the form of the diffusion equation for classical particles moving in a continuous space. A class of classical random processes described by the Schrödinger equation is considered. It is shown that such classical random processes can be used as a tool for the numerical solution of the Schrödinger equation. Citation: International Journal of Quantum Information PubDate: 2016-04-07T08:50:50Z DOI: 10.1142/S0219749916400062