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Showing papers in "International Journal of Theoretical Physics in 2009"


Journal ArticleDOI
TL;DR: In this paper, the Schrodinger equation is solved exactly for some well known potentials and the Nikiforov-Uvarov method is used in the calculations to get energy eigenvalues and the corresponding wave functions.
Abstract: The Schrodinger equation is solved exactly for some well known potentials. Solutions are obtained reducing the Schrodinger equation into a second order differential equation by using an appropriate coordinate transformation. The Nikiforov-Uvarov method is used in the calculations to get energy eigenvalues and the corresponding wave functions.

342 citations


Journal ArticleDOI
TL;DR: In this article, an efficient teleportation scheme for an unknown state to either one of two receivers via GHZ-like states was proposed, and the fidelity of the quantum state when the control party is uncooperative was discussed.
Abstract: We propose an efficient teleportation scheme for an unknown state to either one of two receivers via GHZ-like states. We also discuss the fidelity of the quantum state when the control party is uncooperative.

87 citations


Journal ArticleDOI
TL;DR: In this paper, the generalized physics laws involving fractional derivatives give new models and conceptions that can be used in complex systems having memory effects using the fractional differential forms, the classical electromagnetic equations involving the fractionals derivatives have been worked out.
Abstract: The generalized physics laws involving fractional derivatives give new models and conceptions that can be used in complex systems having memory effects. Using the fractional differential forms, the classical electromagnetic equations involving the fractional derivatives have been worked out. The fractional conservation law for the electric charge and the wave equations were derived by using this method. In addition, the fractional vector and scalar potentials and the fractional Poynting theorem have been derived.

79 citations


Journal ArticleDOI
TL;DR: In this paper, the quantum channel and the amount of information between the senders and the receivers are controlled by the supervisor via his local measurement, where the measurement is determined by the coefficients of the original GHZ-class state in the latter case.
Abstract: Controlled dense coding via multi-particles GHZ state and multi-particles GHZ-class state are exploited in this letter. The quantum channel and the amount of information between the senders and the receivers are controlled by the supervisor via his local measurement. The amount of information is determined by Charlie’s measurement in the former case of GHZ state, and also by the coefficients of the original GHZ-class state in the latter case.

76 citations


Journal ArticleDOI
Yi-You Nie1, Zhi-hui Hong1, Yi-Bin Huang1, Xiao-jie Yi1, Song-Song Li1 
TL;DR: In this paper, a new scheme for controlled teleportation with the help of a four-qubit cluster state is proposed, where the receiver introduces an auxiliary qubit and performs some appropriate unitary transformations on his qubits.
Abstract: A new scheme for controlled teleportation with the help of a four-qubit cluster state is proposed. In this scheme, a four-particle cluster state is shared by a sender, a controller and a receiver. The sender first performs a Bell-basis measurement on the qubits at hand, and the controller performs measurements under a non-maximally entangled Bell-basis after he knows the sender’s measurement result. Then the receiver introduces an auxiliary qubit and performs some appropriate unitary transformations on his qubits. Quantum teleportation is realized after the receiver performs a local measurement on the auxiliary qubit and an appropriate unitary transformation on his qubit.

75 citations


Journal ArticleDOI
TL;DR: In this paper, the authors studied the possibility of obtaining cosmic acceleration in Brans-Dicke theory with varying or constant ω (Brans Dicke parameter) and with or without self-interacting potential, the background fluid being barotropic fluid or Generalized Chaplygin Gas.
Abstract: In this work we have studied the possibility of obtaining cosmic acceleration in Brans-Dicke theory with varying or constant ω (Brans-Dicke parameter) and with or without self-interacting potential, the background fluid being barotropic fluid or Generalized Chaplygin Gas. Here we take the power law form of the scale factor and the scalar field. We show that accelerated expansion can also be achieved for high values of ω for closed Universe.

60 citations


Journal ArticleDOI
TL;DR: In this article, a scheme for remote preparation of the two-particle entangled state by three partial twoparticle entanglement states as the quantum channel is presented, and then directly generalize the scheme for remotely preparing a multipartite GHZ-class state for M senders.
Abstract: For two parties sharing the original state, a scheme for remote preparation of the two-particle entangled state by three partial two-particle entangled states as the quantum channel is presented, and then directly generalize the scheme for remotely preparing a multipartite GHZ-class state for M senders. It is shown that the receiver can obtain the unknown state with certain probability under the condition that only and only if all the senders collaborate with each other. The N-particle projective measurement and the von Neumann measurement are needed in our scheme. The probability of the successful remote state preparation and classical communication cost are calculated.

52 citations


Journal ArticleDOI
TL;DR: Using the Damour-Ruffini-Sannan, the Parikh-Wilczek and the thin film brick-wall model, the authors investigated the Hawking radiation of uncharged massive particles from 4-dimensional linear dilaton black holes.
Abstract: Using the Damour-Ruffini-Sannan, the Parikh-Wilczek and the thin film brick-wall model, we investigate the Hawking radiation of uncharged massive particles from 4-dimensional linear dilaton black holes, which are the solutions to Einstein-Maxwell-Dilaton, Einstein-Yang-Mills-Dilaton and Einstein-Yang-Mills-Born-Infeld-Dilaton theories. Our results show that the tunneling rate is related to the change of Bekenstein-Hawking entropy. Contrary to the many studies in the literature, here the emission spectrum is precisely thermal. This implies that the derived emission spectrum is not consistent with the unitarity of the quantum theory, which would possibly lead to the information loss.

44 citations


Journal ArticleDOI
TL;DR: In this article, the authors propose some cosmological reflections at the qualitative and conjectural level, suggested by the Fantappie-Arcidiacono projective relativity theory.
Abstract: This article proposes some cosmological reflections at the qualitative and conjectural level, suggested by the Fantappie-Arcidiacono projective relativity theory. The difference will firstly be discussed between two types of singularity in this theory: geometric (de Sitter horizon) and physical (big bang, big crunch). The reasons for the existence of geometric singularities are deeply rooted in the principle of inertia and in the principle of relativity, while physical singularities are associated with the creation or destruction of matter.

41 citations


Journal ArticleDOI
TL;DR: In this paper, the relativistic significance of concircular curvature tensors has been explored and the existence of Killing and conformal Killing vectors has been established for spacetimes satisfying Einstein field equations.
Abstract: In the differential geometry of certain F-structures, the importance of concircular curvature tensor is very well known. The relativistic significance of this tensor has been explored here. The spacetimes satisfying Einstein field equations and with vanishing concircular curvature tensor are considered and the existence of Killing and conformal Killing vectors have been established for such spacetimes. Perfect fluid spacetimes with vanishing concircular curvature tensor have also been considered. The divergence of concircular curvature tensor is studied in detail and it is seen, among other results, that if the divergence of the concircular tensor is zero and the Ricci tensor is of Codazzi type then the resulting spacetime is of constant curvature. For a perfect fluid spacetime to possess divergence-free concircular curvature tensor, a necessary and sufficient condition has been obtained in terms of Friedmann-Robertson-Walker model.

38 citations


Journal ArticleDOI
TL;DR: In this article, it was shown that the projections of any object A in such a category form an orthoalgebra Proj A. Sufficient conditions are given to ensure this ortho-algebra is an orthomodular poset.
Abstract: Abramsky and Coecke (Proceedings of the 19th Annual IEEE Symposium on Logic in Computer Science, pp. 415–425, IEEE Comput. Soc., New York, 2004) have recently introduced an approach to finite dimensional quantum mechanics based on strongly compact closed categories with biproducts. In this note it is shown that the projections of any object A in such a category form an orthoalgebra Proj A. Sufficient conditions are given to ensure this orthoalgebra is an orthomodular poset. A notion of a preparation for such an object is given by Abramsky and Coecke, and it is shown that each preparation induces a finitely additive map from Proj A to the unit interval of the semiring of scalars for this category. The tensor product for the category is shown to induce an orthoalgebra bimorphism Proj A×Proj B→Proj (A⊗B) that shares some of the properties required of a tensor product of orthoalgebras.

Journal ArticleDOI
TL;DR: In this paper, Takook et al. proved that quantization in indefinite metric, i.e. QFT in Krein space, removes all divergences of the theory except light cone singularity.
Abstract: It was shown that quantum metric fluctuations smear out the singularities of Green functions on the light cone (Ford, arXiv:gr-qc/9707062), but it does not remove other ultraviolet divergences of the quantum field theory (QFT). We have proved that quantization in indefinite metric, i.e. QFT in Krein space, removes all divergences of the theory except light cone singularity (Gazeau, et al., Class. Quantum Gravity, 17:1415, 2000, arXiv:gr-qc/9904023; Takook, Int. J. Mod. Phys. E, 11:509, 2002, arXiv:gr-qc/0006019). In this paper, by considering the QFT in Krein space and the quantum metric fluctuations, it is shown that all divergences can be removed.

Journal ArticleDOI
TL;DR: In this article, the authors proposed a scheme for the controlled teleportation of an arbitrary two-atom entangled state in driven cavity QED, which does not involve apparent (or direct) Bell-state measurement and is insensitive to the cavity decay and the thermal field.
Abstract: In this paper, we propose a scheme for the controlled teleportation of an arbitrary two-atom entangled state |φ〉12=a|gg〉12+b|ge〉12+c|eg〉12+d|ee〉12 in driven cavity QED. An arbitrary two-atom entangled state can be teleported perfectly with the help of the cooperation of the third side by constructing a three-atom GHZ entangled state as the controlled channel. This scheme does not involve apparent (or direct) Bell-state measurement and is insensitive to the cavity decay and the thermal field. The probability of the success in our scheme is 1.0.

Journal ArticleDOI
TL;DR: In this article, Bianchi type V cosmological models with bulk viscous fluid source were investigated and exact solutions of the Einstein field equations were presented via a suitable power law assumption for the Hubble parameter.
Abstract: We investigate Bianchi type V cosmological models with bulk viscous fluid source. Exact solutions of the Einstein field equations are presented via a suitable power law assumption for the Hubble parameter. We show that the corresponding solutions retain the well established features of the standard cosmology and in addition, are in accordance with recent type Ia supernovae observations. Some observational parameters for the models have also been discussed.

Journal ArticleDOI
TL;DR: In this article, the analytical radial wave functions of the l-wave Klein-Gordon and k-state Dirac equations with the mixed Eckart potentials are presented and the corresponding energy equations are derived.
Abstract: The approximately analytical bound state solutions of the l-wave Klein-Gordon and k-state Dirac equations with the mixed Eckart potentials are carried out by a proper approximation to the centrifugal term. The analytical radial wave functions of the l-wave Klein-Gordon and k-state Dirac equations with the mixed Eckart potentials are presented and the corresponding energy equations are derived. Two special cases for k=1 and for k=1 and β=0 are studied briefly. Finally, we also verify the rationality of this approximation.

Journal ArticleDOI
TL;DR: In this paper, the generalized conformal symmetries and conserved quantities by Lie point transformations of Hamilton systems are studied and the necessary and sufficient conditions of conformal symmetry by the action of infinitesimal Lie point transformation which are simultaneous Lie symmetry are given.
Abstract: In this paper the generalized conformal symmetries and conserved quantities by Lie point transformations of Hamilton systems are studied. The necessary and sufficient conditions of conformal symmetry by the action of infinitesimal Lie point transformations which are simultaneous Lie symmetry are given. This kind type determining equations of conformal symmetry of mechanical systems are studied. The Hojman conserved quantities of the Hamilton systems under infinitesimal special transformations are obtained. The relations between conformal symmetries and the Lie symmetries are derived for Hamilton systems. Finally, as application of the conformal symmetries, an illustration example is introduced.

Journal ArticleDOI
TL;DR: The bound-state solutions of the Dirac equation for the Manning-Rosen potential are presented approximately for arbitrary spin-orbit quantum number κ in this paper, where the energy eigenvalues and corresponding two-component spinors of the two Dirac particles are obtained in the closed form by using the framework of the spin symmetry and pseudospin symmetry concept.
Abstract: The bound-state solutions of the Dirac equation for the Manning-Rosen potential are presented approximately for arbitrary spin-orbit quantum number κ. The energy eigenvalues and corresponding two-component spinors of the two Dirac particles are obtained in the closed form by using the framework of the spin symmetry and pseudospin symmetry concept. Two special cases κ=±1 and the Hulthen potential are briefly investigated.

Journal ArticleDOI
TL;DR: In this paper, a new improved approximation scheme to deal with the centrifugal term and pseudo-centrifugal term was employed to solve the Dirac equation with the hyperbolic potential for the arbitrary spin-orbit quantum number κ.
Abstract: By employing a new improved approximation scheme to deal with the centrifugal term and pseudo-centrifugal term, we solve approximately the Dirac equation with the hyperbolic potential for the arbitrary spin-orbit quantum number κ. Under the condition of the spin and pseudospin symmetry, the bound state energy eigenvalues and the associated two-component spinors of the Dirac particle are obtained approximately by using the basic concept of the supersymmetric shape invariance formalism and the function analysis method.

Journal ArticleDOI
TL;DR: In this article, it was shown that nonholonomically constrained Ricci flows of (pseudo) Riemannian metrics positively result into nonsymmetric metrics (as explicit examples, we consider flows of some physically valuable exact solutions in general relativity).
Abstract: We provide a proof that nonholonomically constrained Ricci flows of (pseudo) Riemannian metrics positively result into nonsymmetric metrics (as explicit examples, we consider flows of some physically valuable exact solutions in general relativity). There are constructed and analyzed three classes of solutions of Ricci flow evolution equations defining nonholonomic deformations of Taub NUT, Schwarzschild, solitonic and pp-wave symmetric metrics into nonsymmetric ones.

Journal ArticleDOI
TL;DR: The fractional generalization of Nambu mechanics is constructed by using the differential forms and exterior derivatives of fractional orders in this paper, where the generalized Pfaffian equations are obtained and one example is investigated in details.
Abstract: The fractional generalization of Nambu mechanics is constructed by using the differential forms and exterior derivatives of fractional orders. The generalized Pfaffian equations are obtained and one example is investigated in details.

Journal ArticleDOI
TL;DR: In this article, the authors dealt with spatially homogeneous and locally rotationally symmetric Bianchi type II cosmological models with bulk viscous fluid distribution of matter and decaying vacuum energy density Λ.
Abstract: The present study deals with spatially homogeneous and locally rotationally symmetric (LRS) Bianchi type II cosmological models with bulk viscous fluid distribution of matter and decaying vacuum energy density Λ. To get the deterministic models of the universe, we assume that the expansion (θ) in the model is proportional to the shear (σ). This leads to condition R=mS n , where R and S are metric potentials, m and n are constants. We have obtained two types of models of the universe for two different values of n. The vacuum energy density Λ for both models is found to be a decreasing function of time and it approaches a small positive value at late time which is supported by recent results from the observations of (SN Ia). Some physical and geometric behaviour of these models are also discussed.

Journal ArticleDOI
TL;DR: In this article, the authors evaluate the energy distribution of the singularity-free solution of the Einstein field equations coupled to a suitable nonlinear electrodynamics suggested by Ayon-Beato and Garcia.
Abstract: According to the Einstein, Weinberg, and Moller energy-momentum complexes, we evaluate the energy distribution of the singularity-free solution of the Einstein field equations coupled to a suitable nonlinear electrodynamics suggested by Ayon-Beato and Garcia. The results show that the energy associated with the definitions of Einstein and Weinberg are the same, but Moller not. Using the power series expansion, we find out that the first two terms in the expression are the same as the energy distributions of the Reissner-Nordstrom solution, and the third term could be used to survey the factualness between numerous solutions of the Einstein field equations coupled to a nonlinear electrodynamics.

Journal ArticleDOI
Abstract: By embedding a free function into a compatible zero curvature equation, we propose a lattice hierarchy with the free function which still admits zero curvature representation. It is interesting that the hierarchy can reduce the Ablowitz-Ladik hierarchy, the Volterra hierarchy and a new hierarchy by properly choosing the embedded function. Moreover, the new hierarchy is integrable in Liouville’s sense and possess multi-Hamiltonian structure.

Journal ArticleDOI
TL;DR: In this article, the fractional multi-time Lagrangian equations for dynamical systems within Riemann-Liouville derivatives were derived and the corresponding fractional Euler-Lagrange and Hamilton equations were obtained.
Abstract: The fractional multi time Lagrangian equations has been derived for dynamical systems within Riemann-Liouville derivatives. The fractional multi time Hamiltonian is introduced as Legendre transformation of multi time Lagrangian. The corresponding fractional Euler-Lagrange and the Hamilton equations are obtained and the fractional multi time constant of motion are discussed.

Journal ArticleDOI
TL;DR: In this paper, the splitting of supersymmetrized Dirac equation in terms of electric and magnetic fields is discussed, and it has been shown that the splitting works well for different cases associated with zero mass, nonzero mass, scalar potential and generalized electromagnetic potentials.
Abstract: Quaternion Dirac equation has been analyzed and its supersymmetrization has been discussed consistently. It has been shown that the quaternion Dirac equation automatically describes the spin structure with its spin up and spin down components of two component quaternion Dirac spinors associated with positive and negative energies. It has also been shown that the supersymmetrization of quaternion Dirac equation works well for different cases associated with zero mass, nonzero mass, scalar potential and generalized electromagnetic potentials. Accordingly we have discussed the splitting of supersymmetrized Dirac equation in terms of electric and magnetic fields.

Journal ArticleDOI
TL;DR: In this article, the authors investigated the possibility of soliton solution in media modeled by the modified complex Ginzburg Landau equation and employed the technique of collective variables (CVs) to obtain a set of six coupled ordinary differential equations, one each for all the CVs included in the ansatz for the pulse.
Abstract: In the present paper, we have investigated the possibility of the existence of soliton solution in media modeled by the modified complex Ginzburg Landau equation. We have employed the technique of collective variables (CVs) to obtain a set of six coupled ordinary differential equations, one each for all the CVs included in the ansatz for the pulse. The coupled differential equations for the collective variables have been numerically solved to reveal the pulse dynamics which show stable soliton propagation.

Journal ArticleDOI
TL;DR: In this paper, the authors consider the energy of the universe from a pseudo-tensor point of view and find zero values, when the calculations are well-done, with the idea that the justification for the calculation lies in the association of the equivalence principle with the nature of co-motional observers, as demanded in Cosmology.
Abstract: We consider the energy of the Universe, from the pseudo-tensor point of view (Berman, M.Sc. thesis, 1981). We find zero values, when the calculations are well-done. The doubts concerning this subject are clarified, with the novel idea that the justification for the calculation lies in the association of the equivalence principle, with the nature of co-motional observers, as demanded in Cosmology. In Sect. 4, we give a novel calculation for the zero-total energy result.

Journal ArticleDOI
TL;DR: In this paper, a class of single-mode excited GHZ-type entangled coherent states (EGHZECSs) is presented and the properties of the EGHZECs, depending on the excitation photon number, are investigated.
Abstract: A class of the single-mode excited GHZ-type entangled coherent states (EGHZECSs) are presented. we exhibit the remarkable properties of the single-mode EGHZECSs, depended on the excitation photon number, such as entanglement and nonlocality via investigating their concurrence of entanglement and examining their violation of CHSH inequality. Finally, we propose how to generate the EGHZECSs by using cavity QED and quantum measurement and by using BBO crystal and single-photon detection technique, respectively.

Journal ArticleDOI
TL;DR: Banerjee et al. as discussed by the authors performed an analysis of the apparent horizon of a black hole using the Hamilton-Jacobi method beyond semiclassical approximation and all the higher order quantum corrections can be given out.
Abstract: An analysis of Hawking radiation about apparent horizon in a FRW universe is performed by using the method developed in the paper (Banerjee, Majhi in JHEP 06:095 2008), in which the Hawking radiation of a black hole is treated as the quantum tunneling by Hamilton-Jacobi method beyond semiclassical approximation and then all the higher order quantum corrections can be given out. In our analysis, the Kodama vector instead of the Killing vector to define the energy of the particle plays a key role. We present our analysis under the Friedmann-Robertson-Walker like coordinate system and the much-like to Painleve coordinate system respectively. The result show that the formulized procedure can be extended to fully analyse the Hawking radiation of a dynamical system.

Journal ArticleDOI
TL;DR: In this article, the generalized second law of thermodynamics holds in Gauss-Bonnet and more general Lovelock gravities in a region of an expanding universe enclosed by the apparent horizon as a thermal system in equilibrium.
Abstract: By employing the general expression for temperature \(T_{h}=|\kappa|/2\pi =\frac{1}{2\pi \tilde{r}_{A}}(1-\frac{\dot{\tilde{r}}_{A}}{2H\tilde{r}_{A}})\) associated with the apparent horizon of FRW universe and assuming a region of an expanding universe enclosed by the apparent horizon as a thermal system in equilibrium, we are able to show that the generalized second law of thermodynamics holds in Gauss-Bonnet and more general Lovelock gravities.