Open Access Published by De Gruyter Open Access

Volume 11 Issue 1

January 2013

Issue of Open Physics

Submit manuscript

Contents
Journal Overview

Open Access January 15, 2013

Symmetric M-theory backgrounds

José Figueroa-O’Farrill

Page range: 1-36

More Download PDF

Abstract

We classify symmetric backgrounds of eleven-dimensional supergravity up to local isometry. In other words, we classify triples (M, g, F), where (M,g) is an eleven-dimensional lorentzian locally symmetric space and F is an invariant 4-form, satisfying the equations of motion of eleven-dimensional supergravity. The possible (M,g) are given either by (not necessarily nondegenerate) Cahen-Wallach spaces or by products AdSd × M11−d for 2 ⩽ d ⩽ 7 and M11−d a not necessarily irreducible riemannian symmetric space. In most cases we determine the corresponding F-moduli spaces.

Open Access January 15, 2013

Exact and approximate solutions of Schrödinger’s equation for a class of trigonometric potentials

Hakan Ciftci, Richard Hall, Nasser Saad

Page range: 37-48

More Download PDF

Abstract

The asymptotic iteration method is used to find exact and approximate solutions of Schrödinger’s equation for a number of one-dimensional trigonometric potentials (sine-squared, double-cosine, tangent-squared, and complex cotangent). Analytic and approximate solutions are obtained by first using a coordinate transformation to reduce the Schrödinger equation to a second-order differential equation with an appropriate form. The asymptotic iteration method is also employed indirectly to obtain the terms in perturbation expansions, both for the energies and for the corresponding eigenfunctions.

Open Access January 15, 2013

Bäcklund transformation for the first flows of the relativistic Toda hierarchy and associated properties

Anindya Choudhury

Page range: 49-58

More Download PDF

Abstract

In this communication we study a class of one parameter dependent auto-Bäcklund transformations for the first flow of the relativistic Toda lattice and also a variant of the usual Toda lattice equation. It is shown that starting from the Hamiltonian formalism such transformations are canonical in nature with a well defined generating function. The notion of spectrality is also analyzed and the separation variables are explicitly constructed.

Open Access January 15, 2013

From massive self-dual p-forms towards gauge p-forms

Silviu-Constantin Sararu

Page range: 59-68

More Download PDF

Abstract

Massive self-dual p-forms are quantized through the construction of an equivalent first-class system and then quantizing the resulting first-class system. The construction of the equivalent first-class system is achieved using the gauge unfixing and constraints conversion BF methods. The Hamiltonian path integral of the first-class system takes a manifestly Lorentz-covariant form.

Open Access January 15, 2013

Notes on entropic characteristics of quantum channels

Alexey Rastegin

Page range: 69-77

More Download PDF

Abstract

One of most important issues in quantum information theory concerns transmission of information through noisy quantum channels. We discuss a few channel characteristics expressed by means of generalized entropies. Such characteristics can often be treated in line with more usual treatment based on the von Neumann entropies. For any channel, we show that the q-average output entropy of degree q ≥ 1 is bounded from above by the q-entropy of the input density matrix. The concavity properties of the (q, s)-entropy exchange are considered. Fano type quantum bounds on the (q, s)-entropy exchange are derived. We also give upper bounds on the map (q, s)-entropies in terms of the output entropy, corresponding to the completely mixed input.

Open Access January 15, 2013

Path integral treatment of a noncentral electric potential

Ali Ghoumaid, Farid Benamira, Larbi Guechi, Zohra Khiat

Page range: 78-88

More Download PDF

Abstract

We present a rigorous path integral treatment of a dynamical system in the axially symmetric potential $V(r,\theta ) = V(r) + \tfrac{1} {{r^2 }}V(\theta ) $ . It is shown that the Green’s function can be calculated in spherical coordinate system for $V(\theta ) = \frac{{\hbar ^2 }} {{2\mu }}\frac{{\gamma + \beta \sin ^2 \theta + \alpha \sin ^4 \theta }} {{\sin ^2 \theta \cos ^2 \theta }} $ . As an illustration, we have chosen the example of a spherical harmonic oscillator and also the Coulomb potential for the radial dependence of this noncentral potential. The ring-shaped oscillator and the Hartmann ring-shaped potential are considered as particular cases. When α = β = γ = 0, the discrete energy spectrum, the normalized wave function of the spherical oscillator and the Coulomb potential of a hydrogen-like ion, for a state of orbital quantum number l ≥ 0, are recovered.

Open Access January 15, 2013

Function projective synchronization of two four-scroll hyperchaotic systems with unknown parameters

Zhenwu Sun

Page range: 89-95

More Download PDF

Abstract

Function projective synchronization (FPS) of two novel hyperchaotic systems with four-scroll attractors which have been found up to the present is investigated. Adaptive control is employed in the situation that system parameters are unknown. Based on Lyapunov stability theory, an adaptive controller and a parameter update law are designed so that the two systems can be synchronized asymptotically by FPS. Numerical simulation is provided to show the effectiveness of the proposed adaptive controller and the parameter update law.

Open Access January 15, 2013

Optomechanical effects in superfluid properties of BEC in an optical lattice

Priyanka Verma, Aranya Bhattacherjee, Man Mohan

Page range: 96-105

More Download PDF

Abstract

We investigate the effects of a movable mirror (cantilever) of an optical cavity on the superfluid properties and the Mott phase boundary of a Bose-Einstein condensate (BEC) in an optical lattice. The Bloch energy, effective mass, Bogoliubov energy and the superfluid fraction are modified due to the mirror motion. The mirror motion is also found to modify the Mott-superfluid phase boundaries. This study reveals that the mirror emerges as a new handle to coherently control the superfluid properties of the BEC.

Open Access January 15, 2013

The phenomenon of super energy flows in the anisotropic left-handed material

Bai Xu, Guan Yu, Li Xia, Zhi Wang

Page range: 106-110

More Download PDF

Abstract

The super energy flows generated and transmitted have been investigated in a parallel-plate waveguide, which is filled with air and the anisotropic left-handed materials. Theoretical analysis and numerical simulations show that the propagation modes of the anisotropic super waveguide are consistent with those of the isotropic waveguides [1–3]. They also show that the loss of electromagnetic parameters size of waveguide will influence the amplitude of time-average power flows.

Open Access January 15, 2013

Excitation spectrum of TTF-TCNQ: a finite temperature calculation

Željana Lošić

Page range: 111-118

More Download PDF

Abstract

In this paper we study the excitation spectrum of the organic conductor tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) using finite temperature calculations. The effect of electronelectron interaction is considered within the random phase approximation (RPA). Our results show the temperature dependent plasmon and dipolar mode corresponding qualitatively to the modes obtained previously using zero temperature formalism assigned to the observed excitations at 10 meV and 0.75 eV. These modes have an essential influence on the energy-loss function. The obtained results are in good qualitative agreement with the optical and EELS data of TTF-TCNQ.

Open Access January 15, 2013

Ferromagnetism in the two-dimensional Hubbard model with long-range hopping

Pavol Farkašovský, Hana Čenčariková

Page range: 119-123

More Download PDF

Abstract

The combination of small-cluster exact-diagonalization calculations and the quantum Monte Carlo method is used to examine ferromagnetism in the two-dimensional Hubbard model with a generalized type of hopping. It is found that the long-range hopping with exponentially decaying hopping amplitudes t ij ∼ − q Ri−Rj stabilizes the ferromagnetic state for a wide range of electron interactions U and electron concentrations n > 1. The critical value of the hopping parameter q c above which the ferromagnetic state becomes stable is calculated numerically and the ground-state phase diagram of the model is discussed for physically the most interesting cases.

Open Access January 15, 2013

Ordering of the O(2)…D… O(2) bonds near the phase transition in KD3(SeO3)2 single crystals by D nuclear magnetic resonance

Ae Lim, Se-Young Jeong

Page range: 124-129

More Download PDF

Abstract

Deuterium resonance investigations of KD3(SeO3)2 single crystals have been performed near the phase transition temperature T C. There are two types of deuterium bonds in these crystals with different behaviors at this phase transition. Our experimental results show that there are significant changes in the D spinlattice relaxation time T 1 at T C; the abrupt decrease in T 1 near T C can be explained by the critical slowing down of an overdamped soft pseudospin-type deuteron mode. Further, the ordering of the O(2)…D… O(2) bonds is affected by the phase transition, whereas the ordering of the O(1)-D… O(3) bonds is unaffected. The D NMR measurements also show that the D(2) deuteron disordering above T C is dynamic and not static.

Open Access January 15, 2013

Temperature dependence of the optical properties of Bi2O3. A theoretical approach basing on the Kramers-Kronig transformation for polynomial mixed terms models

Gabriel Murariu, Simona Condurache-Bota

Page range: 130-137

More Download PDF

Abstract

The Kramers-Kronig transforms (KK) constitute a powerful tool to validate experimental data. The present study is implemented for Bi2O3 thin films deposited by thermal vacuum evaporation at different temperatures of the glass substrates. Since the extraordinary properties of this fabric allow us to consider particular analytical approach as it was previously shown, the reflectance properties of Bi2O3 as a function of temperature could be studied. The novelty of this article is the studying of a global effective analytical representation, based on polynomial functions, in order to obtain a general model that includes temperature dependence of the optical properties, using the Kramers-Kronig transformation type. In the mathematical expressions, were included mix combined term in order to avoid the effects of Runge phenomenon. As a case study was chosen Bi2O3 — a substance less studied in literature. In the last part are the presented and commented the results obtained for a series of eight studied models.

Open Access January 15, 2013

Effect of thermal annealing in air on scintillation properties of LuAG and LuAG:Pr

Kamil Brylew, Winicjusz Drozdowski, Marcin Witkowski, Kei Kamada, Takayuki Yanagida, Akira Yoshikawa

Page range: 138-142

More Download PDF

Abstract

Pure and Pr-activated Lu3Al5O12 (LuAG) crystals have been grown by the Czochralski method. In order to improve the scintillation properties, several samples have been annealed in air. Various annealing temperatures and periods of time have been tested to determine optimal conditions in the way of scintillation yield and energy resolution enhancement. The largest increase of yield of LuAG:Pr (17%), accompanied by a distinct decrease of resolution, has been observed after annealing at 1100°C for 48 h. On the contrary, in case of undoped LuAG no significant changes following thermal annealing have been noticed.

Open Access January 15, 2013

An eighth-order KdV-type equation in (1+1) and (2+1) dimensions: multiple soliton solutions

Abdul-Majid Wazwaz

Page range: 143-146

More Download PDF

Abstract

In this work we study an eighth-order KdV-type equations in (1+1) and (2+1) dimensions. The new equations are derived from the KdV6 hierarchy. We show that these equations give multiple soliton solutions the same as the multiple soliton solutions of the KdV6 hierarchy except for the dispersion relations.

About this journal

Open Physics (PHYS) is a peer-reviewed, open access, electronic journal devoted to the publication of fundamental research results in all fields of physics. The journal provides the readers with free, instant, and permanent access to all content worldwide; and the authors with extensive promotion of published articles, long-time preservation, no space constraints and immediate publication.

Aims and Scope

The journal publishes research and review articles, rapid and short communications, comments and replies that cover the following areas of physical sciences:

Acoustics

Astrophysics,

Atomic and Molecular Physics,

Biological and Medical Physics,

Complex Networks, Socio- and Econophysics,

Computational Physics,

Condensed Matter Physics,

Cosmology and Gravitation,

Fluid Mechanics,

Geophysics,

Nanophysics,

Optics and Lasers,

Particle and Nuclear Physics,

Plasma Physics,

Statistical and Nonlinear Physics,

Surface Physics,

Theoretical and Mathematical Physics.