Shape Invariant and Rodrigues Solution of?the?Dirac-shifted Oscillator and?Dirac-Morse Potentials

We show that the Dirac equation for a charged spinor in spherically symmetric electromagnetic potentials as Dirac-shifted oscillator and Dirac-Morse potentials have the conditions of shape invariant symmetry in non-relativistic quantum mechanics. The relativistic spectra of the bound states and spinor wavefunctions can be obtained by the Rodrigues polynomials of one associated differential equation.     

Is Physics Simple? Yes and No

No Abstract.  .     

Quantum Teleportation and Quantum Information Splitting by?Using?a?Genuinely?Entangled Six-Qubit State

A new application of the genuinely entangled six-qubit state introduced recently by Tapiador et al. (J. Phys. A 42:415301, 2009) is investigated for the quantum teleportation of an arbitrary three-qubit state and for quantum information splitting (QIS) of an arbitrary two-qubit state. For QIS, we have shown that it can be completed perfectly with two distinct measurement methods. In our scheme, the joint Bell-state measurement and the joint multi-qubit measurement are needed. This quantum teleportation and QIS schemes are deterministic.     

Wigner Functions and Tomograms of?the?Klauder-Perelomov Coherent States for?the?Pseudoharmonic Oscillator

Using the coherent state representation of Wigner operator and the technique of integration within an ordered product (IWOP) of operators, the Wigner functions of the Klauder-Perelomov coherent states (KP-CSs) for the pseudoharmonic oscillator (PHO) are obtained and the variations of the Wigner functions with the parameters k and z are discussed. Moreover, the tomograms of the KP-CSs for the PHO are calculated by virtue of intermediate coordinate-momentum representation in quantum optics. Project 10574060 supported by the National Natural Science Foundation of China and project X071049 supported by Science Foundation of Liaocheng University.     

Spectral structure of 510.6 and 578.2 nm lines in?a?CuBr?vapor?laser

Considering the hyperfine structure and the isotopic splitting of copper active atomic levels, the temporal behavior of the spectral structure of amplified spontaneous emission at 510.6 nm line was calculated. The spectral line shapes of 510.6 and 578.2 nm laser lines were measured and compared with the calculated results at different experimental configurations, i.e., without cavity mirrors, with the back mirror, and with cavity mirrors. The results of the 578.2 nm line revealed that the mode competition was involved in the formation of laser oscillation.     

Characterization and ammonia sensing properties of pure and?modified ZnO films

Zinc oxide (ZnO) films have been prepared by thermal oxidation of pre-deposited zinc films on the glass substrate kept at room temperature. These films were surface modified by dipping them into an aqueous solution (0.1 M) of lithium chloride (LiCl) and aluminium chloride (AlCl₃) followed by firing at 500°C. Based on X-ray diffraction results it is observed that modification of pure ZnO by lithium and aluminium precursor results a change in the lattice parameters. Li and Al ions appear to enhance the a-axis orientation and c-axis orientation of pure ZnO films, respectively. Field emission scanning electron micrographs of lithium-modified ZnO film indicate the presence of nanoneedles, while nanorods are observed in case of aluminium-modified ZnO film. The electrical resistance measurements of modified ZnO films also show variation in resistance as compared to pure ZnO film. Pure and Al-modified films of ZnO are sensitive to ammonia at room temperature, while Al-modified ZnO film is found to be more sensitive with 99% of response at 250 ppm.     

Highly dynamic and versatile pulsed fiber amplifier seeded?by?a?superluminescence diode

We propose and investigate a high power superluminescence diode (SLD) as a pulsed seed source for a highly dynamic and versatile pulse fiber amplifier system. The SLD provides, contrary to conventional Fabry?CPérot laser diodes, a smooth and broad output spectrum which is independent of the input pulse parameters. The output pulses from the SLD are as short as 10?ns with up to 150?mW peak power. Moreover, the pulses can be directly shaped by modulating the injection current of the SLD. Pulse shaping in an amplifier configuration is demonstrated without the observation of stimulated Brillouin scattering (SBS) due to the provided spectral bandwidth of 10?nm FWHM. Further spectral shaping was realized with a band pass filter in the amplifier chain.     

Magnetic, structural, and thermal properties of CoV?O?

In this paper, we investigate the electric, magnetic, structural, and thermal properties of spinel CoV(2)O(4). The temperature dependence of magnetization shows that, in addition to the paramagnetic-to-ferrimagnetic transition at T(C) = 142 K, two magnetic anomalies exist at 100 K, T(1) = 59 K. Consistent with the anomalies, the thermal conductivity presents two valleys at 100 K and T(1). At the temperature T(1), the heat capacity shows one peak, which cannot be attributed to the structural transition as revealed by the x-ray diffraction patterns for CoV(2)O(4). Below the transition temperature T(1), the ac susceptibility displays the characteristics of a glass. The series of phenomena at T(1) and the orbital state on V(3+) sites are discussed.     

Adsorption of carboxymethylester-azobenzene on copper and?gold?single crystal surfaces

The adsorption of 3,3′-di(methoxycarbonyl)azobenzene (CMA) on Au(111) and on Cu(001) substrates was studied by X-ray absorption spectroscopy measurements at the C, N, and O K edges. We find the molecules physisorbed in a planar conformation flat on the Au(111) surface. At higher coverages, a molecular crystal is formed wherein the molecules have the same flat geometry. On Cu(001), additional chemical bonds are formed between the molecules and the surface via the nitrogen atoms. Here the methyl benzoate moieties are tilted out of the surface plane.     

Might Dark Matter and Energy be Intrinsic Properties of?Space?

It is shown that if a volume element V, of space is assumed to have intrinsic energy E, then basic principles of mechanics, thermodynamics and special relativity lead to the equation of state: E=pV, where p is the pressure. When this equation of state is incorporated in the Einstein equations it leads to the prediction that the orbital speed of matter circling a visible galaxy embedded in a spherical galactic halo should be relativistic, in disagreement with observations. However, it also leads directly to the interesting notion that the inertial mass of such a medium can be understood as a resistance to being compressed via Lorentz contraction. It is then shown that the mathematical structure of thermodynamics suggests another plausible definition of pressure if we allow for the possibility that the intrinsic energy of spacetime may not be described by the same work-energy relationship as ordinary matter. This additional possibility leads to the equation of state: E=−pV. While both of these equations of state describe forms of energy that are quite unlike ordinary energy, neither alone is able to account for observed rotational velocity curves of matter orbiting visible galaxies. Therefore, the possibility that space has two distinct components of energy is investigated. This results in a plausible, two-component equation of state in which the former equation of state is tentatively identified as the “dark matter” (DM) component, the latter as the “dark energy” (DE) component. The effective equation of state of space, accounting for the presence of both components, may then be written in the form: p=w ε, where ε is the total energy density, p the total pressure, and w represents the fractional excess of DM over DE (and therefore satisfies: −1≤w≤+1). Given the wide range of possible spacetime properties implied by this equation it appears to be a viable candidate for explaining observations presently attributed to the presence of both DM and DE. Specifically, the static, spherically symmetric solution of Einstein’s field equations, neglecting effects of ordinary matter, predicts the inverse r ² distribution of intrinsic space energy required to explain observed constant rotational velocity curves for matter in circular orbits around visible galaxies embedded within spherically symmetric galactic halos. The proposed equation of state is also capable of describing regions of space undergoing accelerated expansion as regions where DE is dominant (i.e., w<−1/3).     

Phase transition between three- and two-flavor QCD?

We explore the possibility that QCD may undergo a phase transition as a function of the strange quark mass. This would hint towards models with ”spontaneous color symmetry breaking” in the vacuum. For two light quark flavors we classify possible colored quark-antiquark, diquark and gluon condensates that are compatible with a spectrum of integer charged states and conserved isospin and baryon number. The ”quark mass phase transition” would be linked to an unusual realization of baryon number in QCD₂ and could be tested in lattice simulations. We emphasize, however, that at the present stage the Higgs picture of the vacuum cannot predict a quark mass phase transition - a smooth crossover remains as a realistic alternative. Implications of the Higgs picture for the high-density phase transition in QCD₂ suggest that this transition is characterized by the spontaneous breaking of isospin for nuclear and quark matter. Received: 12 March 2001 / Revised version: 2 April 2003 / Published online: 2 June 2003 RID="a" ID="a" e-mail: C.Wetterich@thphys.uni-heidelberg.de     

The Dynamical Behaviour of Test Particles in?a?Quasi-spherical Spacetime and the?Physical Meaning?of?Superenergy

We calculate the instantaneous proper radial acceleration of test particles (as measured by a locally defined Lorentzian observer) in a Weyl spacetime, close to the horizon. As expected from the Israel theorem, there appear some bifurcations with respect to the spherically symmetric case (Schwarzschild) which are explained in terms of the behaviour of the superenergy, bringing out the physical relevance of this quantity in the study of general relativistic systems.     

From entropy and jet quenching to deconfinement?

The challenge of demonstrating that the matter produced in heavy ion collisions is a deconfined quark-gluon plasma, as predicted by lattice QCD calculations, is the challenge of measuring the number of thermodynamic degrees of freedom at the time t₀ at which the matter comes into approximate local thermal equilibrium and begins to behave like a hydrodynamic fluid. Data from experiments done at the Relativistic Heavy Ion Collider have been used to estimate t₀ and to put a lower bound on the energy density . However, measuring has seemed out of reach, because no current data serve even as qualitative proxies for the temperature T(t₀). We point out that may equally appropriately be defined via , where s is the entropy density, which can be estimated from the measured final state entropy. This estimate is based on the testable assumption of an isentropic expansion. The observation of jet quenching has the potential to provide an upper bound on the energy density at early times. Our goal is to motivate such an analysis by pointing out that it would set a lower bound on .Received: 18 February 2005, Revised: 14 April 2005, Published online: 31 May 2005     

Quantization: Deformation and/or Functor?

After a short presentation of the difference in motivation between the Berezin and deformation quantization approaches, we start with a reminder of Berezin’s view of quantization as a functor followed by a brief overview of deformation quantization in contrast with the latter. We end by a short survey of two main avatars of deformation quantization, quantum groups and quantum spaces (especially noncommutative geometry) presented in that perspective.     

Why optical data communications and why now?

Our focus here is on data communications within IT equipment and in IT data centers. Optical communications is not new. Thus the obvious question is likely; why a paper entitled, “Why optical data communications and why now?”. The reasons are twofold. First, optical data communications is more necessary now than it has ever been in the past. It is not excessive to even consider that it will be required in the not too distant future. Second, the advances in the broad field of photonics and optics have brought optical communications nearly to the point that it can finally cross over the threshold to be less expensive than electronic signaling. In this paper we make the case why we must aggressively pursue optics for data communications at all length scales within the data center. The summarization of this paper is that optical communications is inevitable, and we offer reasons why we believe this is true.     

Randomness in Classical Mechanics and?Quantum Mechanics

The Copenhagen interpretation of quantum mechanics assumes the existence of the classical deterministic Newtonian world. We argue that in fact the Newton determinism in classical world does not hold and in the classical mechanics there is fundamental and irreducible randomness. The classical Newtonian trajectory does not have a direct physical meaning since arbitrary real numbers are not observable. There are classical uncertainty relations: Δq>0 and Δp>0, i.e. the uncertainty (errors of observation) in the determination of coordinate and momentum is always positive (non zero).     

Electronic structure and energetics of tetragonal SrCuO? and its high-pressure superstructure phase

First-principles calculations have been used to investigate the electronic structure and energetics of the simple tetragonal SrCuO? (P4=mmm) and its high-pressure tetragonal superstructure (P4=mmm). Based on the calculations, the high-pressure phase is metastable as compared with the low pressure tetragonal phase, with an energy difference of 0.13 eV per SrCuO? formula unit. The energy barrier to the transition from the superstructure to the simple tetragonal structure is 0.24 eV at 7 GPa; thus, high temperatures are required to synthesize the latter. Among the possible structural configurations resulting from the partially occupied oxygen site in the superstructure phase, the most stable structure has a space group PN4m2, reduced from that of the simple tetragonal structure P4=mmm. The detailed analysis of the electronic band structures of the simple tetragonal and superstructure phases suggests that the out-of-plane buckling of the O atoms in the superstructure leads to significant decrease in the O p-Cu d orbital overlap, allowing the energy of the system to be lowered, which is necessary for the structural stability. An understanding of the electronic structure and energetics of the high-pressure superstructure phase and its relation to the simple tetragonal phase provides a basis for exploring the physical properties of the infinite layer, high-TC superconductor.     

B?cklund Transformation and Solutions for the Long-Wave and Short-Wave Resonance Equations and Their Extending System

By using Painlevé analysis, we derive the Backlund transformation for the longwave and short-wave resonance equations and their extending systems. Then we take some constraints of the B?ckJund transformation and find some solutions.