It is shown that the Dirac equation is separable by variables in a five-dimensional rotating Kerr-(anti-)de Sitter black hole with two independent angular momenta. A first-order symmetry operator that commutes with the Dirac operator is constructed in terms of a rank-three Killing-Yano tensor whose square is a second-order symmetric Stäckel-Killing tensor admitted by the five-dimensional Kerr-(...

The imaginary part of the exchange-correlation kernel in the longitudinal current-current response function of a quasi-onedimensional Fermi liquid is evaluated by an approximate decoupling in the equation of motion for the current density, which accounts for processes of excitation of two particle-hole pairs. The two-pair spectrum determines the intrinsic damping rate of long-wavelength collect...

This article presents visualizations of some solutions of the timedependent free Dirac equation. They illustrate some of the strange phenomena which are caused by the interference of positiveand negative-energy waves. We discuss, in particular, the conditions for the occurrence of effects like the Zitterbewegung , the opposite direction of momentum and velocity in negative-energy wave packets, ...

Using the Nikiforov-Uvarov method, an application of the relativistic Duffin-Kemmer-Petiau equation in the presence of a deformed Hulthen potential is presented for spin zero particles. We derived the first-order coupled differential radial equations which enable the energy eigenvalues as well as the full wavefunctions to be evaluated by using of the Nikiforov-Uvarov method that can be written ...

A Dirac particle is represented by a unitarily evolving state vector in a Hilbert space which factors as Hspin Hposition. Motivated by the similarity to simple models of decoherence consisting of a two state system coupled to an environment, we investigate the occurence of decoherence in the Dirac equation upon tracing over position. We conclude that the physics of this mathematically exact mod...

introduction saffron (crocus sativus l.) is a subtropical plant mostly cultivated in south khorasan and khorasan razavi provinces, iran. total saffron production is about 200 ton all over the world, and since it is native to iran, the country has an important role to produce saffron. in recent years, drought showed a significant effect on water resources in birjand, south khorasan. due to lack ...

varicocele is one of the most common causes of primary male infertility. pilea microphylla (pm) is being used as folk medicine. this study was aimed to investigate the effects of pm in a rat model of varicocele. a total of 30 male wistar rats were divided into control, sham, varicocele, accessory varicocele and pm-treated groups. after 10 weeks of varicocele induction, sperm parameters and chro...

A popular three-dimensional reduction of the Bethe–Salpeter formalism for the description of bound states in quantum field theory is the Salpeter equation, derived by assuming both instantaneous interactions and free propagation of all bound-state constituents. Numerical (variational) studies of the Salpeter equation with confining interaction, however, observed specific instabilities of the so...