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  Subjects -> PHYSICS (Total: 750 journals)
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PHYSICS (543 journals)            First | 1 2 3 4 5 6 | Last

International Journal of PIXE     Hybrid Journal   (Followers: 1)
International Journal of Plasticity     Hybrid Journal   (Followers: 6)
International Journal of Quantum Information     Hybrid Journal  
International Journal of Self-Propagating High-Temperature Synthesis     Hybrid Journal   (Followers: 2)
International Journal of Solids and Structures     Hybrid Journal   (Followers: 10)
International Journal of Surface Science and Engineering     Hybrid Journal   (Followers: 7)
International Journal of Theoretical and Applied Multiscale Mechanics     Hybrid Journal   (Followers: 2)
International Journal of Theoretical and Mathematical Physics     Open Access   (Followers: 1)
International Journal of Theoretical Physics     Hybrid Journal   (Followers: 2)
International Journal of Thermal Sciences     Hybrid Journal   (Followers: 5)
Inverse Problems     Hybrid Journal   (Followers: 4)
IOP Conference Series: Materials Science and Engineering     Open Access   (Followers: 3)
ISRN Astronomy and Astrophysics     Open Access   (Followers: 11)
ISRN Condensed Matter Physics     Open Access  
ISRN High Energy Physics     Open Access  
ISRN Mathematical Physics     Open Access  
ISRN Nanotechnology     Open Access  
ISRN Spectroscopy     Open Access  
Izvestiya Atmospheric and Oceanic Physics     Hybrid Journal   (Followers: 3)
Izvestiya, Physics of the Solid Earth     Hybrid Journal   (Followers: 4)
Japanese Journal of Applied Physics     Full-text available via subscription   (Followers: 3)
JCP : BioChemical Physics     Hybrid Journal  
JETP Letters     Hybrid Journal   (Followers: 3)
Journal of Adhesion Science and Technology     Hybrid Journal   (Followers: 6)
Journal of Advances in Physics     Open Access   (Followers: 3)
Journal of Applied Mathematics and Mechanics     Full-text available via subscription   (Followers: 5)
Journal of Applied Mathematics and Physics     Open Access  
Journal of Applied Mechanics and Technical Physics     Hybrid Journal   (Followers: 3)
Journal of Applied Physics     Hybrid Journal   (Followers: 188)
Journal of Applied Remote Sensing     Full-text available via subscription   (Followers: 11)
Journal of Applied Spectroscopy     Hybrid Journal   (Followers: 7)
Journal of Astrophysics     Open Access  
Journal of Astrophysics and Astronomy     Open Access   (Followers: 10)
Journal of Basic and Applied Physics     Open Access   (Followers: 1)
Journal of Building Physics     Hybrid Journal   (Followers: 1)
Journal of Chromatographic Science     Hybrid Journal   (Followers: 20)
Journal of Complex Networks     Hybrid Journal  
Journal of Composite Materials     Hybrid Journal   (Followers: 51)
Journal of Computational Methods in Physics     Open Access  
Journal of Computational Physics     Hybrid Journal   (Followers: 190)
Journal of Contemporary Physics (Armenian Academy of Sciences)     Hybrid Journal   (Followers: 1)
Journal of Dynamic Systems, Measurement, and Control     Full-text available via subscription   (Followers: 7)
Journal of Elasticity     Hybrid Journal   (Followers: 2)
Journal of Electrical Bioimpedance     Full-text available via subscription   (Followers: 2)
Journal of Electron Spectroscopy and Related Phenomena     Hybrid Journal   (Followers: 2)
Journal of Electronic Materials     Hybrid Journal   (Followers: 5)
Journal of Electronics Cooling and Thermal Control     Open Access   (Followers: 1)
Journal of Engineering Materials and Technology     Full-text available via subscription   (Followers: 15)
Journal of Engineering Physics and Thermophysics     Hybrid Journal  
Journal of Experimental and Theoretical Physics     Hybrid Journal   (Followers: 3)
Journal of Fire Sciences     Hybrid Journal   (Followers: 2)
Journal of Geometry and Physics     Full-text available via subscription  
Journal of Geophysical Research : Space Physics     Full-text available via subscription   (Followers: 16)
Journal of Gravity     Open Access  
Journal of High Energy Physics     Hybrid Journal   (Followers: 2)
Journal of Hyperspectral Remote Sensing     Open Access   (Followers: 1)
Journal of Information Display     Hybrid Journal  
Journal of Intelligent Material Systems and Structures     Hybrid Journal   (Followers: 3)
Journal of Lightwave Technology     Hybrid Journal   (Followers: 6)
Journal of Low Frequency Noise, Vibration and Active Control     Full-text available via subscription   (Followers: 6)
Journal of Luminescence     Hybrid Journal   (Followers: 2)
Journal of Magnetic Resonance     Hybrid Journal   (Followers: 4)
Journal of Materials Engineering and Performance     Hybrid Journal   (Followers: 6)
Journal of Materials Physics and Chemistry     Open Access  
Journal of Materials Science     Hybrid Journal   (Followers: 17)
Journal of Materials Science : Materials in Electronics     Hybrid Journal   (Followers: 4)
Journal of Materials Science : Materials in Medicine     Hybrid Journal   (Followers: 6)
Journal of Mathematical Fluid Mechanics     Hybrid Journal   (Followers: 4)
Journal of Mathematical Physics     Hybrid Journal   (Followers: 3)
Journal of Medical Ultrasonics     Hybrid Journal   (Followers: 2)
Journal of Micro/Nanolithography MEMS and MOEMS     Hybrid Journal   (Followers: 3)
Journal of Modern Physics     Open Access   (Followers: 2)
Journal of Molecular Spectroscopy     Hybrid Journal   (Followers: 6)
Journal of Motor Behavior     Hybrid Journal   (Followers: 7)
Journal of Multiscale Modeling     Hybrid Journal  
Journal of Nanophotonics     Full-text available via subscription   (Followers: 4)
Journal of Neutron Research     Hybrid Journal  
Journal of Nondestructive Evaluation     Hybrid Journal   (Followers: 4)
Journal of Nonlinear Dynamics     Open Access  
Journal of Nonlinear Mathematical Physics     Hybrid Journal   (Followers: 1)
Journal of Nuclear Physics, Material Sciences, Radiation and Applications     Open Access  
Journal of Optics     Hybrid Journal   (Followers: 2)
Journal of Physical and Chemical Reference Data     Hybrid Journal   (Followers: 2)
Journal of Physical Chemistry B     Full-text available via subscription   (Followers: 27)
Journal of Physical Chemistry C     Full-text available via subscription   (Followers: 21)
Journal of Physical Oceanography     Full-text available via subscription   (Followers: 9)
Journal of Physical Organic Chemistry     Hybrid Journal   (Followers: 7)
Journal of Physics A : Mathematical and Theoretical     Hybrid Journal   (Followers: 3)
Journal of Physics and Chemistry of Solids     Hybrid Journal   (Followers: 4)
Journal of Physics D : Applied Physics     Hybrid Journal   (Followers: 11)
Journal of Physics: Condensed Matter     Hybrid Journal   (Followers: 7)
Journal of Physics: Conference Series     Open Access   (Followers: 3)
Journal of Plasma Physics     Hybrid Journal   (Followers: 4)
Journal of Polymer Science Part B: Polymer Physics     Hybrid Journal   (Followers: 22)
Journal of Porous Materials     Hybrid Journal   (Followers: 3)
Journal of Porphyrins and Phthalocyanines     Hybrid Journal   (Followers: 2)
Journal of Quantitative Spectroscopy and Radiative Transfer     Hybrid Journal  
Journal of Reinforced Plastics and Composites     Hybrid Journal   (Followers: 5)
Journal of Research in Physics     Open Access  
Journal of Rheology     Full-text available via subscription   (Followers: 4)

  First | 1 2 3 4 5 6 | Last

Journal Cover International Journal of Quantum Information
   Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 0219-7499 - ISSN (Online) 1793-6918
     Published by World Scientific Homepage  [114 journals]   [SJR: 0.588]   [H-I: 18]
  • Entanglement generation in the ultra-strongly coupled Rabi model
    • Authors: Matteo Bina, Stefano Maffezzoli Felis, Stefano Olivares
      Abstract: International Journal of Quantum Information, Ahead of Print. We analyze the dynamics of the quantum Rabi model for two qubits interacting through a common bosonic field (resonator), focusing on the generation and detection of maximally entangled states. We obtain analytical results for the unitary dynamics of this system in the slow-qubit (or degenerate) regime, considering ultra-strong coupling between qubits and resonator mode, for which the rotating wave approximation (RWA) is no longer applicable. We also numerically investigate the dynamics beyond the slow-qubit condition in order to study the validity of the model in the presence of less strict conditions.
      Citation: International Journal of Quantum Information
      PubDate: Thu, 18 Dec 2014 07:09:18 GMT
      DOI: 10.1142/S0219749915600163
       
  • Experimental hybrid entanglement between quantum and classical states of
           light
    • Authors: Luca S. Costanzo, Alessandro Zavatta, Samuele Grandi, Marco Bellini, Hyunseok Jeong, Minsu Kang, Seung-Woo Lee, Timothy C. Ralph
      Abstract: International Journal of Quantum Information, Ahead of Print. The realization of hybrid entanglement between a microscopic (quantum) and a macroscopic (classical) system, in analogy to the situation of the famous Schrödinger's cat paradox, is an important milestone, both from the fundamental perspective and for possible applications in the processing of quantum information. The most straightforward optical implementation of this condition is that of the entanglement between a single-photon and a coherent state. In this work, we describe the first step towards the generation of this type of hybrid entanglement from the experimental perspective.
      Citation: International Journal of Quantum Information
      PubDate: Wed, 17 Dec 2014 08:57:58 GMT
      DOI: 10.1142/S0219749915600151
       
  • Entanglement generation and dynamics for a Bose–Hubbard model in a
           double-well potential
    • Authors: F. Gentile, A. Montorsi, M. Roncaglia
      Abstract: International Journal of Quantum Information, Ahead of Print. The study of entanglement between bosonic systems is of primary importance for establishing feasible resources needed for implementing quantum information protocols, both in their interacting atomic or photonic realizations. Atomic systems are particularly efficient in the production of large amounts of entanglement, providing higher information density than conventional qubit entangled states. Such increased quantum resources pave the way to novel fundamental tests of nature and efficient applications in quantum information, metrology and sensing. We consider a basic setup made up of two parties A and B, each one populated by a single level bosonic variable. The bosons are interacting and can hop between A and B, thus describing a two-site Bose–Hubbard Hamiltonian. We consider the generation of quantum states in several situations that cover the majority of physical realizations: ground state, finite temperature, unitary dynamics, dissipation through dephasing and loss of particles. The system is analyzed through truncated exact diagonalization, as a function of the microscopic parameters. The nonseparability of the obtained quantum states is estimated by means of the negativity, which has recently been proven to be a suitable measure of entanglement [M. Roncaglia, A. Montorsi and M. Genovese, Phys. Rev. A90 (2014) 062303]. Finally, we calculate lower bounds of the entanglement of formation (EOF), an indicator that quantifies the minimal amount of entanglement resources needed to build up such states.
      Citation: International Journal of Quantum Information
      PubDate: Wed, 10 Dec 2014 09:56:34 GMT
      DOI: 10.1142/S021974991560014X
       
  • Quantum discord in spin-1/2 Heisenberg chains with
           Dzyaloshinkii–Moriya interaction
    • Authors: Xiao San Ma, An Min Wang
      Abstract: International Journal of Quantum Information, Ahead of Print. We have investigated the quantum discord (QD) of the thermal density matrix of spin-1/2 Heisenberg chains with Dzyaloshinskii–Moriya (DM) interaction. With fermionization technique, we study the mutual effect of DM interaction and the external magnetic field on the QD and the entanglement. Our analysis implies that the DM interaction can enhance the QD while the external magnetic field will shrink the QD. By a comparison between the entanglement and the QD, we find that the QD is more robust to the temperature and to the external magnetic field than the entanglement of formation (EoF) in the sense that the EoF takes a zero value while the QD does not for high temperature and strong external magnetic field. This point confirms the conclusion that there exist some separable states containing non-zero QD.
      Citation: International Journal of Quantum Information
      PubDate: Wed, 10 Dec 2014 09:56:33 GMT
      DOI: 10.1142/S0219749914500439
       
  • Single-photon emitters based on NIR color centers in diamond coupled with
           solid immersion lenses
    • Authors: D. Gatto Monticone, J. Forneris, M. Levi, A. Battiato, F. Picollo, P. Olivero, P. Traina, E. Moreva, E. Enrico, G. Brida, I. P. Degiovanni, M. Genovese, G. Amato, L. Boarino
      Abstract: International Journal of Quantum Information, Ahead of Print. Single-photon sources represent a key enabling technology in quantum optics, and single color centers in diamond are a promising platform to serve this purpose, due to their high quantum efficiency and photostability at room temperature. The widely studied nitrogen-vacancy (NV) centers are characterized by several limitations, thus other defects have recently been considered, with a specific focus of centers emitting in the near-infra red (NIR). In the present work, we report on the coupling of native NIR-emitting centers in high-quality single-crystal diamond with solid immersion lens (SIL) structures fabricated by focused ion beam (FIB) lithography. The reported improvements in terms of light collection efficiency make the proposed system an ideal platform for the development of single-photon emitters with appealing photophysical and spectral properties.
      Citation: International Journal of Quantum Information
      PubDate: Wed, 10 Dec 2014 09:56:33 GMT
      DOI: 10.1142/S0219749915600114
       
  • High-capacity imaging and rotationally insensitive object identification
           with correlated orbital angular momentum states
    • Authors: Casey A. Fitzpatrick, David S. Simon, Alexander V. Sergienko
      Abstract: International Journal of Quantum Information, Ahead of Print. Using no conventional measurements in position space, information extraction rates exceeding one bit per photon are achieved by employing high-dimensional correlated orbital angular momentum (OAM) states for object recognition. The correlations are shown to be insensitive to axial rotation of the target object: The information structure of an object's joint OAM coincidence spectrum is unchanged even when the object undergoes random rotations between each measurement. Additionally, OAM correlations alone are shown to be sufficient for full image reconstruction of complex, off-axis objects, and novel object symmetries are observed in the phases of OAM-object interaction transition amplitudes. Variations in mutual information rates, due to off-axis translation in the beam field, are studied, and it is shown that object symmetry signatures and information rates are independent of environmental factors sufficiently far from the beam center. The results motivate dynamic scanning applications in contexts where symmetry and small numbers of noninvasive measurements are desired.
      Citation: International Journal of Quantum Information
      PubDate: Tue, 09 Dec 2014 10:14:58 GMT
      DOI: 10.1142/S0219749915600138
       
  • Hunting the "impossible atoms" Pauli exclusion principle violation and
           spontaneous collapse of the wave function at test
    • Authors: Catalina Curceanu, Sergio Bartalucci, Angelo Bassi, Sergio Bertolucci, Carolina Berucci, Alexandru Mario Bragadireanu, Michael Cargnelli, Alberto Clozza, Sergio Di Matteo, S. Donadi, Alessandro D'uffizi, J.-P. Egger, Carlo Guaraldo, Mihail Iliescu, Tomoichi Ishiwatari, Matthias Laubenstein, Johann Marton, Edoardo Milotti, Dorel Pietreanu, Kristian Piscicchia, Titus Ponta, Emanuele Sbardella, Alessandro Scordo, Hexi Shi, Diana Sirghi, Florin Sirghi, Laura Sperandio, Oton Vazquez Doce, Johann Zmeskal
      Abstract: International Journal of Quantum Information, Ahead of Print. The Pauli exclusion principle (PEP) and, more generally, the spin-statistics connection, are at the very basis of our understanding of matter, life and Universe. The PEP spurs, presently, a lively debate on its possible limits, deeply rooted in the very foundations of Quantum Mechanics. It is, therefore, extremely important to test the limits of its validity. The Violation of the PEP (VIP) experiment established the best limit on the probability that PEP is violated by electrons, using the method of searching for PEP forbidden atomic transitions in copper. We describe the experimental method, the obtained results, and plans to go beyond the actual limit by upgrading the experimental apparatus. We discuss the possibility of using 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 (CSL) theories.
      Citation: International Journal of Quantum Information
      PubDate: Tue, 09 Dec 2014 10:14:55 GMT
      DOI: 10.1142/S0219749915600126
       
  • The su(1,1)-like intensity-dependent Rabi model: A perturbative analysis
           of weak and strong-coupling regimes
    • Authors: Vittorio Penna, Francesco A. Raffa
      Abstract: International Journal of Quantum Information, Ahead of Print. We present a perturbative analysis of a Rabi model where the coupling between the quantized single-mode electromagnetic field and the two-level atom depends on the field intensity. Upon modeling the matter–radiation coupling through the Holstein–Primakoff realization of algebra su(1,1), we evaluate first- and second-order eigenenergies and eigenstates both in the weak-coupling regime (atom transition frequency smaller than the coupling strength) and in the strong-coupling regime. In the first case, among various effects, we observe a quadratic dependence on the photon number of energy eigenvalues and the possible formation of level doublets. In the strong-coupling case, the perturbative analysis becomes considerably complex due to the su(1,1)-valued form of the unperturbed Hamiltonian. The critical condition for the transition to an almost continuous spectrum is found in terms of the model parameters.
      Citation: International Journal of Quantum Information
      PubDate: Wed, 03 Dec 2014 04:06:43 GMT
      DOI: 10.1142/S0219749915600102
       
  • Features of three-photon polarization states: Entanglement and
           polarization
    • Authors: M. V. Fedorov
      Abstract: International Journal of Quantum Information, Ahead of Print. In a general form, three-photon polarization states are superpositions of contributions from four three-photon polarization modes with four arbitrary complex coefficients. Entanglement of such states is defined as entanglement between their one-photon and two-photon parts. The degree of entanglement is found explicitly in terms of such entanglement quantifiers as the generalized concurrence, entropy of reduced states and the Schmidt parameter. Polarization Stokes vectors, as well as the Schmidt decompositions of three-photon states are found and discussed. Similarity and differences with respect to biphoton polarization states are discussed too.
      Citation: International Journal of Quantum Information
      PubDate: Wed, 03 Dec 2014 04:00:01 GMT
      DOI: 10.1142/S0219749915600096
       
  • Quantifying the leakage of quantum protocols for classical two-party
           cryptography
    • Authors: Louis Salvail, Christian Schaffner, Miroslava Sotáková
      Abstract: International Journal of Quantum Information, Ahead of Print. We study quantum protocols among two distrustful parties. By adopting a rather strict definition of correctness — guaranteeing that honest players obtain their correct outcomes only — we can show that every strictly correct quantum protocol implementing a non-trivial classical primitive necessarily leaks information to a dishonest player. This extends known impossibility results to all non-trivial primitives. We provide a framework for quantifying this leakage and argue that leakage is a good measure for the privacy provided to the players by a given protocol. Our framework also covers the case where the two players are helped by a trusted third party. We show that despite the help of a trusted third party, the players cannot amplify the cryptographic power of any primitive. All our results hold even against quantum honest-but-curious adversaries who honestly follow the protocol but purify their actions and apply a different measurement at the end of the protocol. As concrete examples, we establish lower bounds on the leakage of standard universal two-party primitives such as oblivious transfer.
      Citation: International Journal of Quantum Information
      PubDate: Wed, 03 Dec 2014 04:00:01 GMT
      DOI: 10.1142/S0219749914500415
       
  • Is quantum simulation of turbulence within reach'
    • Authors: Mario Rasetti
      Abstract: International Journal of Quantum Information, Ahead of Print. The possibility of approaching quantum simulation of "topological turbulence" is discussed. In the latter, the topological features of turbulent flow are ascribed to a purely group-theoretic and topological view through the group SDiff of volume-preserving diffeomorphisms and the Mapping Class Group for the 2D surfaces that foliate the 3D flow domain. A class of representations of the group of mapping classes for compact boundaryless surfaces is explicitly constructed in terms of the Witt–Virasoro Hopf-coalgebra and implemented in terms of su(1,1). This leads to a complex, nonlinear Hamiltonian naturally associated with the fluid diffeomorphisms that could lend itself to the quantum simulation of turbulence in Fock space.
      Citation: International Journal of Quantum Information
      PubDate: Mon, 01 Dec 2014 06:09:05 GMT
      DOI: 10.1142/S0219749915600084
       
  • Quantum dissonance and deterministic quantum computation with a single
           qubit
    • Authors: Mazhar Ali
      Abstract: International Journal of Quantum Information, Ahead of Print. Mixed state quantum computation can perform certain tasks which are believed to be efficiently intractable on a classical computer. For a specific model of mixed state quantum computation, namely, deterministic quantum computation with a single qubit (DQC1), recent investigations suggest that quantum correlations other than entanglement might be responsible for the power of DQC1 model. However, strictly speaking, the role of entanglement in this model of computation was not entirely clear. We provide conclusive evidence that there are instances where quantum entanglement is not present in any part of this model, nevertheless we have advantage over classical computation. This establishes the fact that quantum dissonance (a kind of quantum correlations) present in fully separable (FS) states provide power to DQC1 model.
      Citation: International Journal of Quantum Information
      PubDate: Mon, 01 Dec 2014 06:09:05 GMT
      DOI: 10.1142/S0219749914500373
       
  • Quantum codes from cyclic codes over F3 + vF3
    • Authors: Mohammad Ashraf et al
      Abstract: International Journal of Quantum Information, Ahead of Print. Let R = F3 + vF3 be a finite commutative ring, where v2 = 1. It is a finite semi-local ring, not a chain ring. In this paper, we give a construction for quantum codes from cyclic codes over R. We derive self-orthogonal codes over F3 as Gray images of linear and cyclic codes over R. In particular, we use two codes associated with a cyclic code over R of arbitrary length to determine the parameters of the corresponding quantum code.
      PubDate: Thu, 20 Nov 2014 08:53:12 GMT
      DOI: 10.1142/S0219749914500427
       
  • Emerging quantum mechanics: Coefficient of second-order coherence from
           classical random fields interacting with threshold type detectors
    • Authors: Andrei Khrennikov
      Abstract: International Journal of Quantum Information, Ahead of Print. 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 g2(0) calculations are too complicated and only an estimation of g2(0) was 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 Browninan motion in the space of classical fields (Wiener process in complex Hilbert space). Simulation for g2(0) shows that this coefficient approaches zero with increase of the number of detections.
      PubDate: Tue, 18 Nov 2014 09:07:28 GMT
      DOI: 10.1142/S0219749915600072
       
  • Entanglement and other quantum correlations of a single qudit state
    • Authors: Margarita A. Man'ko et al
      Abstract: International Journal of Quantum Information, Ahead of Print. The approach to extend the notion of entanglement for characterizing the properties of quantum correlations in the state of a single qudit is presented. New information and entropic inequalities, such as the subadditivity condition, strong subadditivity condition, and monotonicity of relative entropy for a single qudit corresponding to an arbitrary spin state with spin j are discussed. The idea to employ quantum correlations in the single-qudit state, such as the entanglement, for developing a new quantum technique in quantum computing and quantum communication is proposed. Examples of qutrit and qudit with j = 3/2 are considered.
      PubDate: Tue, 18 Nov 2014 09:07:25 GMT
      DOI: 10.1142/S0219749915600060
       
  • Engineering nonlinear coherent states as photon-added and
           photon-subtracted coherent states
    • Authors: I. Ramos-Prieto et al
      Abstract: International Journal of Quantum Information, Ahead of Print. We propose a class of nonlinear coherent states which are experimentally feasible in cavity or ion-trap quantum electrodynamics. These quantum field states arise from a new type of photon addition and subtraction based on London phase operators, also known as Susskind–Glogower operators, that just displaces the mean photon number without scaling the photon distribution.
      PubDate: Tue, 11 Nov 2014 08:02:08 GMT
      DOI: 10.1142/S0219749915600059
       
  • Dimension-independent bounds for Hardy's experiment
    • Authors: Zhen-Peng Xu et al
      Abstract: International Journal of Quantum Information, Ahead of Print. Hardy's paradox is of fundamental importance in quantum information theory. So far, there have been two types of its extensions into higher dimensions: in the first type the maximum probability of nonlocal events is roughly 9% and remains the same as the dimension changes (dimension-independent), while in the second type the probability becomes larger as the dimension increases, reaching approximately 40% in the infinite limit. Here, we (i) give an alternative proof of the first type, (ii) study the situation in which the maximum probability of nonlocal events can also be dimension-independent in the second type and (iii) conjecture how the situation could be changed in order that (ii) still holds.
      PubDate: Tue, 11 Nov 2014 08:02:07 GMT
      DOI: 10.1142/S0219749914500397
       
  • One-party controlled minimum remote state preparation of equatorial
           n-qubit states
    • Authors: Yahong Wang et al
      Abstract: International Journal of Quantum Information, Ahead of Print. This paper offers a theoretical protocol for one-party controlled remote state preparation (RSP) of n-qubit states with minimum resources consumption. We are mainly focused on the case of the n-qubit state chosen from equatorial circle on a Bloch sphere. We use n - 1 EPR pairs and one GHZ state as quantum channel and show that only n + 1 cbits, n ebits and 2n + 1 qubits are consumed during the controlled RSP processing.
      PubDate: Tue, 11 Nov 2014 08:02:03 GMT
      DOI: 10.1142/S0219749914500385
       
  • Quantum nonlocality enhanced by homogenization
    • Authors: Xu Chen et al
      Abstract: International Journal of Quantum Information, Ahead of Print. Homogenization proposed in [Y.-C Wu and M. Żukowski, Phys. Rev. A85 (2012) 022119] is a procedure to transform a tight Bell inequality with partial correlations into a full-correlation form that is also tight. In this paper, we check the homogenizations of two families of n-partite Bell inequalities: the Hardy inequality and the tight Bell inequality without quantum violation. For Hardy's inequalities, their homogenizations bear stronger quantum violation for the maximally entangled state; the tight Bell inequalities without quantum violation give the boundary of quantum and supra-quantum, but their homogenizations do not have the similar properties. We find their homogenization are violated by the maximally entangled state. Numerically computation shows the the domains of quantum violation of homogenized Hardy's inequalities for the generalized GHZ states are smaller than those of Hardy's inequalities.
      PubDate: Tue, 11 Nov 2014 08:02:02 GMT
      DOI: 10.1142/S0219749914500403
       
  • Comment on "Cryptanalysis and improvement of the secure quantum sealed-bid
           auction with post confirmation"
    • Authors: Zhangji Zhao et al
      Abstract: International Journal of Quantum Information, Ahead of Print. In a recent paper,1 an improvement of quantum sealed-bid auction protocol is proposed by introducing hash function. However, in this comment, it is shown that the improvement brings in other problems which would not complete the task of a sealed-bid auction fairly.
      PubDate: Fri, 07 Nov 2014 09:28:49 GMT
      DOI: 10.1142/S021974991475001X
       
  • Pairwise quantum and classical correlations in multi-qubits states via
           linear relative entropy
    • Authors: M. Daoud et al
      Abstract: International Journal of Quantum Information, Ahead of Print. The pairwise correlations in a multi-qubit state are quantified through a linear variant of relative entropy. In particular, we derive the explicit expressions of total, quantum and classical bipartite correlations. Two different bi-partioning schemes are considered. We discuss the derivation of closest product, quantum–classical and quantum–classical product states. We also investigate the additivity relation between the various pairwise correlations existing in pure and mixed states. As illustration, some special cases are examined.
      PubDate: Wed, 05 Nov 2014 03:45:36 GMT
      DOI: 10.1142/S021974991450035X
       
  • Time exponents of asymptotic entanglement of discrete quantum walk in one
           dimension
    • Authors: Recep Eryiğit et al
      Abstract: International Journal of Quantum Information, Ahead of Print. We report a systematic study of asymptotic behavior of entanglement between the position and coin degrees of freedom for a one-dimensional discrete quantum walk. Effects of coin bias, initial coin asymmetry and phase difference and non-locality of initial position state on the fluctuations and asymptotic value of entanglement are investigated by using Fourier approach. Fluctuations in entropy are found to die out as power law in time as t-α with α = 1/2,3/2 and 5/2 depending on the initial state parameters of the system.
      PubDate: Wed, 05 Nov 2014 03:45:36 GMT
      DOI: 10.1142/S0219749914500361
       
  • A bonding model of entanglement for N-qubit graph states
    • Authors: Mordecai Waegell
      Abstract: International Journal of Quantum Information, Ahead of Print. The class of entangled N-qubit states known as graph states, and the corresponding stabilizer groups of N-qubit Pauli observables, have found a wide range of applications in quantum information processing and the foundations of quantum mechanics. A review of the properties of graph states is given and core spaces of graph states are introduced and discussed. A bonding model of entanglement for generalized graph states is then presented, in which the presence or absence of a bond between two qubits unequivocally specifies whether or not they are entangled. A physical interpretation of these bonds is given, along with a characterization of how they can be created or destroyed by entangling unitary operations and how they can be destroyed by local Pauli measurements. It is shown that local unitary operations do not affect the bond structure of a graph state, and therefore that if two graph states have nonisomorphic bond structures, then local unitary operations and/or reordering of qubits cannot change one into the other. Color multigraphs are introduced to depict the bond structures of graph states and to make some of their properties more apparent.
      PubDate: Fri, 31 Oct 2014 04:14:30 GMT
      DOI: 10.1142/S0219749914300058
       
  • The intrinsic helicity of elementary particles and the spin-statistic
           connection
    • Authors: Francesco De Martini et al
      Abstract: International Journal of Quantum Information, Ahead of Print. The traditional standard quantum mechanics (SQM) is unable to solve the spin-statistics problem, i.e. to justify the utterly important "Pauli exclusion principle". The present paper presents a simple and complete solution of the spin-statistics problem on the basis of the "conformal quantum geometrodynamics (CQG)", a theory that was found to reproduce successfully all relevant processes of the SQM based on Dirac's or Schrödinger's equations, including Heisenberg's uncertainty relations and non-local Einstein–Podolsky–Rosen (EPR) correlations. When applied to a system made of many identical particles, an additional property of all elementary particles enters naturally into play: the "intrinsic helicity". This property, not considered in the SQM, determines the correct spin-statistics connection (SSC) observed in nature.
      PubDate: Wed, 29 Oct 2014 04:22:03 GMT
      DOI: 10.1142/S0219749915600047
       
  • Universal optimal quantum correlator
    • Authors: Francesco Buscemi et al
      Abstract: International Journal of Quantum Information, Ahead of Print. Recently, a novel operational strategy to access quantum correlation functions of the form Tr[AρB] was provided in [F. Buscemi, M. Dall'Arno, M. Ozawa and V. Vedral, arXiv:1312.4240]. Here we propose a realization scheme, that we call partial expectation values, implementing such strategy in terms of a unitary interaction with an ancillary system followed by the measurement of an observable on the ancilla. Our scheme is universal, being independent of ρ, A, and B, and it is optimal in a statistical sense. Our scheme is suitable for implementation with present quantum optical technology, and provides a new way to test uncertainty relations.
      PubDate: Tue, 28 Oct 2014 09:40:50 GMT
      DOI: 10.1142/S0219749915600023
       
  • Engineering decoherence for two-qubit systems interacting with a classical
           environment
    • Authors: Matteo A. C. Rossi et al
      Abstract: International Journal of Quantum Information, Ahead of Print. We address the dynamics of a two-qubit system interacting with a classical dephasing environment driven by a Gaussian stochastic process. Upon introducing the concept of entanglement-preserving time, we compare the degrading effects of different environments, e.g. those described by Ornstein–Uhlenbeck (OU) or fractional noise. In particular, we consider pure Bell states and mixtures of Bell states and study the typical values of the entanglement-preserving time for both independent and common environments. We found that engineering environments towards fractional Gaussian noise is useful to preserve entanglement as well as to improve its robustness against noise. We also address entanglement sudden death by studying the sudden-death time as a function of the initial negativity. We found that: (i) the sudden-death time is bounded from below by an increasing function of the initial negativity, (ii) the sudden-death time depends only slightly on the process used to describe the environment and exhibits typicality. Overall, our results show that engineering the environment has only a slight influence over the entanglement sudden-death time, while it represents a valuable resource to increase the entanglement-preserving time, i.e. to maintain entanglement closer to the initial level for a longer interaction time.
      PubDate: Tue, 21 Oct 2014 08:49:45 GMT
      DOI: 10.1142/S0219749915600035
       
  • If time is a local observable, then Hawking radiation is unitary
    • Authors: Hrvoje Nikolić
      Abstract: International Journal of Quantum Information, Ahead of Print. In the usual formulation of quantum theory, time is a global classical evolution parameter, not a local quantum observable. On the other hand, both canonical quantum gravity (which lacks fundamental time-evolution parameter) and the principle of spacetime covariance (which insists that time should be treated on an equal footing with space) suggest that quantum theory should be slightly reformulated, in a manner that promotes time to a local observable. Such a reformulated quantum theory is unitary in a more general sense than the usual quantum theory. In particular, this promotes the non-unitary Hawking radiation to a unitary phenomenon, which avoids the black-hole information paradox.
      PubDate: Tue, 19 Aug 2014 11:39:12 GMT
      DOI: 10.1142/S0219749915600011
       
  • Limitations on quantum dimensionality reduction
    • Authors: sales@wspc.com.sg (Aram W. Harrow)
      Abstract: International Journal of Quantum Information, Ahead of Print. The Johnson–Lindenstrauss Lemma is a classic result which implies that any set of n real vectors can be compressed to O(logn) dimensions while only distorting pairwise Euclidean distances by a constant factor. Here we consider potential extensions of this result to the compression of quantum states. We show that, by contrast with the classical case, there does not exist any distribution over quantum channels that significantly reduces the dimension of quantum states while preserving the 2-norm distance with high probability. We discuss two tasks for which the 2-norm distance is indeed the correct figure of merit. In the case of the trace norm, we show that the dimension of low-rank mixed states can be reduced by up to a square root, but that essentially no dimensionality reduction is possible for highly mixed states.
      PubDate: Wed, 04 Jun 2014 03:58:56 GMT
      DOI: 10.1142/S0219749914400012
       
  • EXPLICIT RELATION BETWEEN ALL LOWER BOUND TECHNIQUES FOR QUANTUM QUERY
           COMPLEXITY
    • Authors: LOÏCK MAGNIN et al
      Abstract: International Journal of Quantum Information, Volume 0, Issue 0, Ahead of Print.
      PubDate: Mon, 25 Nov 2013 06:28:10 GMT
      DOI: 10.1142/S0219749913500597
       
 
 
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