2015年, 第64卷, 第03期　
刊出日期：2015-09-01

  

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  Exact Analytical Solution of the Klein-Gordon Equation in the Generalized Woods-Saxon Potential

  O. Bayrak, D. Sahin

  理论物理通讯. 2015, 64(03): 259-262.

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  The exact analytical solution of the Klein-Gordon equation for the spin-0 particles in the generalized Woods-Saxon potential is presented. The bound state energy eigenvalues and corresponding wave functions are obtained in the closed forms. The correlations between the potential parameters and energy eigenvalues are examined for π⁰ particles.
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  Two-Dimensional Linear Dependencies on the Coordinate Time-Dependent Interaction in Relativistic Non-Commutative Phase Space

  H. Sobhani, H. Hassanabadi

  理论物理通讯. 2015, 64(03): 263-268.

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  In this paper, the Non-Commutative phase space and Dirac equation, time-dependent Dirac oscillator are introduced. After presenting the desire general form of a two-dimensional linear dependency on the coordinate time-dependent potential, the Dirac equation is written in terms of Non-Commutative phase space parameters and solved in a general form by using Lewis-Riesenfield invariant method and the time-dependent invariant of Dirac equation with two-dimensional linear dependency on the coordinate time-dependent potential in Non-Commutative phase space has been constructed, then such latter operations are done for time-dependent Dirac oscillator. In order to solve the differential equation of wave function time evolution for Dirac equation and time-dependent Dirac oscillator which are partial differential equation some appropriate ordinary physical problems have been studied and at the end the interesting result has been achieved.
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  Approximate Solutions of Dirac Equation with Hyperbolic-Type Potential

  Altuğ Arda, Ramazan Sever

  理论物理通讯. 2015, 64(03): 269-273.

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  The energy eigenvalues of a Dirac particle for the hyperbolic-type potential field have been computed approximately. It is obtained a transcendental function of energy, F(E), by writing in terms of confluent Heun functions. The numerical values of energy are then obtained by fixing the zeros on "E-axis" for both complex functions Re[F(E)] and Im[F(E)].
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  A Protocol to Estimate the Average Fidelity of the Space-Separated Bipartite System

  黄龙, 吴小华

  理论物理通讯. 2015, 64(03): 274-280.

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  In present work, we show that the average fidelity of a bipartite system can be decided by the average survive probability of the product state and the average survive probability of each subsystem. Several protocols to measure these quantities are constructed. Our method is suitable for the cases where the bipartite system is space-separated.
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  Complete Analysis of Four-Photon χ-Type Entangled State via Cross-Kerr Nonlinearity

  曾志, 李熙涵, 王纯, 汪粒粒, 刘真真, 魏华

  理论物理通讯. 2015, 64(03): 281-286.

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  We propose an efficient method to construct an optical four-photon |χ> state analyzer via the cross-Kerr nonlinearity combined with linear optical elements. In this protocol, two four-qubit parity-check gates and two controlled phase gates are employed. We show that all the 16 orthogonal four-qubit |χ> states can be completely discriminated with our apparatus. The scheme is feasible and realizable with current technology. It may have useful potential applications in quantum information processing which based on |χ> state.
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  Teleportation with Multiple Accelerated Partners

  A. Sagheer, H. Hamdoun, N. Metwally

  理论物理通讯. 2015, 64(03): 287-294.

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  As the current revolution in communication is underway, quantum teleportation can increase the level of security in quantum communication applications. In this paper, we present a quantum teleportation procedure that capable to teleport either accelerated or non-accelerated information through different quantum channels. These quantum channels are based on accelerated multi-qubit states, where each qubit of each of these channels represents a partner. Namely, these states are the W state, Greenberger-Horne-Zeilinger (GHZ) state, and the GHZ-like state. Here, we show that the fidelity of teleporting accelerated information is higher than the fidelity of teleporting non-accelerated information, both through a quantum channel that is based on accelerated state. Also, the comparison among the performance of these three channels shows that the degree of fidelity depends on type of the used channel, type of the measurement, and value of the acceleration. The result of comparison concludes that teleporting information through channel that is based on the GHZ state is more robust than teleporting information through channels that are based on the other two states. For future work, the proposed procedure can be generalized later to achieve communication through a wider quantum network.
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  Tomographic Approach in Three-Orthogonal-Basis Quantum Key Distribution

  梁文烨, 温浩, 银振强, 陈华, 李宏伟, 陈巍, 韩正甫

  理论物理通讯. 2015, 64(03): 295-298.

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  At present, there is an increasing awareness of some three-orthogonal-basis quantum key distribution protocols, such as, the reference-frame-independent (RFI) protocol and the six-state protocol. For secure key rate estimations of these protocols, there are two methods: one is the conventional approach, and another is the tomographic approach. However, a comparison between these two methods has not been given yet. In this work, with the general model of rotation channel, we estimate the key rate using conventional and tomographic methods respectively. Results show that conventional estimation approach in RFI protocol is equivalent to tomographic approach only in the case of that one of three orthogonal bases is always aligned. In other cases, tomographic approach performs much better than the respective conventional approaches of the RFI protocol and the six-state protocol. Furthermore, based on the experimental data, we illustrate the deep connections between tomography and conventional RFI approach representations.
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  Multi-Bit Quantum Private Query

  石惟旭, 刘星彤, 王剑, 唐朝京

  理论物理通讯. 2015, 64(03): 299-304.

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  Most of the existing Quantum Private Queries (QPQ) protocols provide only single-bit queries service, thus have to be repeated several times when more bits are retrieved. Wei et al.'s scheme for block queries requires a high-dimension quantum key distribution system to sustain, which is still restricted in the laboratory. Here, based on Markus Jakobi et al.'s single-bit QPQ protocol, we propose a multi-bit quantum private query protocol, in which the user can get access to several bits within one single query. We also extend the proposed protocol to block queries, using a binary matrix to guard database security. Analysis in this paper shows that our protocol has better communication complexity, implementability and can achieve a considerable level of security.
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  Sub-Fidelity and Super-Fidelity Between Gaussian States

  齐霄霏, 王丽

  理论物理通讯. 2015, 64(03): 305-308.

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  In this paper, we analyze the sub-fidelity and super-fidelity of an arbitrary pair of n-mode Gaussian states. Particularly, an explicit formula for the sub-fidelity and super-fidelity between any two-mode Gaussian states is obtained.
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  Dark Solitons for the Defocusing Cubic Nonlinear Schrödinger Equation with the Spatially Periodic Potential and Nonlinearity

  闫振亚, 闫方驰

  理论物理通讯. 2015, 64(03): 309-319.

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  We study the existence of dark solitons of the defocusing cubic nonlinear Schrödinger (NLS) eqaution with the spatially-periodic potential and nonlinearity. Firstly, we propose six families of upper and lower solutions of the dynamical systems arising from the stationary defocusing NLS equation. Secondly, by regarding a dark soliton as a heteroclinic orbit of the Poincaré map, we present some constraint conditions for the periodic potential and nonlinearity to show the existence of stationary dark solitons of the defocusing NLS equation for six different cases in terms of the theory of strict lower and upper solutions and the dynamics of planar homeomorphisms. Finally, we give the explicit dark solitons of the defocusing NLS equation with the chosen periodic potential and nonlinearity.
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  Directed Transport of Brownian Particles in a Periodic Channel

  江捷, 艾保全, 吴建春

  理论物理通讯. 2015, 64(03): 320-324.

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  The transport of Brownian particles in the infinite channel within an external force along the axis of the channel has been studied. In this paper, we study the transport of Brownian particle in the infinite channel within an external force along the axis of the channel and an external force in the transversal direction. In this more sophisticated situation, some property is similar to the simple situation, but some interesting property also appears.
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  Pion and σ-meson Properties in a Strong Magnetic Field

  张锐, 付伟杰, 刘玉鑫

  理论物理通讯. 2015, 64(03): 325-333.

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  With the Nambu-Jona-Lasinio (NJL) model we calculate the properties of pion and σ-meson at finite temperature and finite magnetic field. The obtained temperature and magnetic field strength dependence of the constituent quark mass M, the pion and σ-meson masses and the neutral pion decay constant indicates that, in the simple four fermion interaction model, there exists the magnetic catalysis effect. It also shows that the Gell-Mann-Oakes-Renner relation is violated obviously with the increasing of the temperature, and the effect of the magnetic field becomes pronounced only around the critical temperature. The deviation of the critical temperatures obtained with different criteria indicates that the chiral phase transition driven by the temperature in the magnetic field strength region we have considered is in fact a crossover.
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  Residue Coulomb Interaction Among Isobars and Its Influence in Symmetry Energy of Neutron-Rich Fragment

  马春旺, 王闪闪, 张艳丽, 赵艺龙, 魏慧玲

  理论物理通讯. 2015, 64(03): 334-340.

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  The residue Coulomb interaction (RCI), which affects the result of symmetry-energy coefficient of neutron-rich nucleus in isobaric yield ratio (IYR) method, is difficult to be determined. Four RCI approximations are investigated: (i) The M1-RCI adopting the a_c/T (the ratio of Coulomb energy coefficient to temperature) determined from the IYR of mirror-nucleus fragments; (ii) The M2-RCI by fitting the difference between IYRs; (iii) The M3-RCI adopting the standard Coulomb energy at a temperature T=2 MeV; and (iv) Neglecting the RCI among isobars. The M1-, M2- and M3-RCI are no larger than 0.4. In particular, the M2-RCI is very close to zero. The effects of RCI in a_sym/T of fragment are also studied. The M1- and M4-a_sym/T are found to be the lower and upper limitations of a_sym/T, respectively. The M2-a_sym/T overlaps the M4-a_sym/T, which indicates that the M2-RCI is negligible in the IYR method, and the RCI among the three isobars can be neglected. The relative consistent low values of M3-a_sym/T (7.5±2.5) are found in very neutron-rich isobars.
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  Production of the Superposition of Nonlinear Coherent States and Entangled Nonlinear Coherent States

  A. Karimi, M. K. Tavassoly

  理论物理通讯. 2015, 64(03): 341-344.

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  In this paper, by using the parity operator as well as the nonlinear displacement-type operator, we define new operators which by the action of them on the vacuum state of the radiation field, superposition of two nonlinear coherent states and two-mode entangled nonlinear coherent states are generated. Also, we show that via the generalization of the presented method, the superposition of more than two nonlinear coherent states and n-mode entangled nonlinear coherent states can be generated.
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  Thermodynamic Comparison and the Ideal Glass Transition of Antiferromagnetic Ising Model on Multi-branched Husimi and Cubic Recursive Lattice with the Identical Coordination Number

  黄然, Purushottam D. Gujrati

  理论物理通讯. 2015, 64(03): 345-355.

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  Two types of recursive lattices with the identical coordination number but different unit cells (2-D square and 3-D cube) are constructed and the antiferromagnetic Ising model is solved exactly on them to study the stable and metastable states. A multi-branched structure of the 2-D plaquette model, which we introduced in this work, makes it possible to be an analog to the cubic lattice. Two solutions of each model can be found to exhibit the crystallization of liquid, and the ideal glass transition of supercooled liquid respectively. Based on the solutions, the thermodynamics on both lattices, e.g. the free energy, energy density, and entropy of the supercooled liquid, crystal, and liquid state of the model are calculated and compared with each other. Interactions between particles farther away than the nearest neighbor distance and multi-spins interactions are taken into consideration, and their effects on the thermal behavior are examined. The two lattices show comparable properties on the thermodynamics, which proves that both of them are practical to describe the regular 3-D case, especially to locate the ideal glass transition, while the 2-D multi-branched plaquette model is less accurate with the advantage of simpler formulation and less computation time consumption.
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  Quantum Correlation in Matrix Product States of One-Dimensional Spin Chains

  祝敬敏

  理论物理通讯. 2015, 64(03): 356-360.

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  For our proposed composite parity-conserved matrix product state (MPS), if only a spin block length is larger than 1, any two such spin blocks have correlation including classical correlation and quantum correlation. Both the total correlation and the classical correlation become larger than that in any subcomponent; while the quantum correlations of the two nearest-neighbor spin blocks and the two next-nearest-neighbor spin blocks become smaller and for other conditions the quantum correlation becomes larger, i.e., the increase or the production of the long-range quantum correlation is at the cost of reducing the short-range quantum correlation, which deserves to be investigated in the future; and the ration of the quantum correlation to the total correlation monotonically decreases to a steady value as the spacing spin length increasing.
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  Thermoelectric Properties of Single Molecule Junction in Presence of Dephasing and Different Coupling Geometries

  Z. Golsanamlou, M. Bagheri Tagani, H. Rahimpour Soleimani

  理论物理通讯. 2015, 64(03): 361-366.

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  The thermoelectric properties of a benzene molecule coupled to three-dimensional metallic electrodes are examined in the presence of dephasing processes using Green function formalism in the linear response regime. The three different kind of configurations (ortho, meta and para) are taken into account for the coupling between the molecule and electrodes. Results show that the thermoelectric properties of the single molecular junction are strongly dependent on the coupling geometry. Our results predict that the thermoelectric efficiency is increased in specific geometry as a consequence of interference effects. It is found that the dephasing effects result in the reduction of the thermoelectric efficiency.