Narrow Results

In this paper, we consider a charged relativistic spin-1 oscillator under the influence of an internal magnetic flux in a $(2+1)$-dimensional spacetime induced by a spinning point source. In order to analyze the effects of the internal magnetic flux and spin of the point source on the relativistic dynamics of such a vector field, we seek a non-perturbative solution of the associated spin-1 equation derived as an excited state of Zitterbewegung. By performing an analytical solution of the resulting equation, we determine exact results for the system in question. Accordingly, we analyze the effects of spin of the point source and internal magnetic flux on the relativistic dynamics of the considered test field. We see that the spin of such a field can be altered by the magnetic flux and this means that the considered system may behave as a fermion or boson according to the varying values of the magnetic flux, in principle. We observe that the internal magnetic flux and the spin of the point source impact on the relativistic energy levels and probability density functions. Also, our results indicate that the spin of the point source breaks the symmetry of the energy levels corresponding to particle–antiparticle states.

The flux associated with the electron's spin is calculated on a the basis of the magnetic top (spherical top) model which can be made equivalent to a circular current loop with radius R in x–y plane in the presence of a uniform magnetic field in z-direction. It is found that the flux associated with the electron's spin is exactly equal to +Φ₀/2 for a spin down electron and -Φ₀/2 spin up one.

The flux creep phenomena and the J_c characteristics have been investigated in the YBa₂Cu₃O₇ (YBCO) thin films grown by metal organics chemical vapor deposition (MOCVD) technique. The anisotropy of the current density (J_c) is discussed on the basis of the intrinsic pinning model and the anisotropic critical magnetic field (H_c2). The properties of the high J_c and the pinning energy are related with the fine precipitates observed by tunneling electron microscopy (TEM). The strong pinning mechanism affects the amount of the flux motion.

In this study, we propose a new bilayer-laminated magnetoelectric (ME) composite consisting of magnetostrictive Ni and Tb${}_{0.3}$Dy${}_{0.7}$Fe₂ (Terfenol-D) plates and piezoelectric Pb(Zr,Ti)O₃ (PZT) plate. The Ni–Terfenol–D-Ni/PZT composite is constructed and compared with the traditional Terfenol-D/PZT composite. The bias magnetic field and the electric field frequency dependences of the converse ME (CME) coefficient were investigated. It is shown that the Ni–Terfenol-D–Ni/PZT exhibits a large CME coefficient of 6.2 × 10${}^{-7}$ s/m at the electric field frequency of 42 kHz under a low bias magnetic field of 230 Oe, which results from the highly concentrated flux induced by Ni and the stress-interaction between Ni and magnetostrictive Terfenol-D.

The influences of phase noise together with autapse on the resonance dynamics in a modified FitzHugh–Nagumo (FHN) neuron are investigated by numerical simulation, where the neuronal model is in the environment of electromagnetic induction. First, it is found that phase noise can induce double coherence resonances, which is further confirmed to be robust to the feedback gain of induction current. Surprisingly, by individually changing the period of phase noise and the feedback gain, a resonance-like behavior also appears. Subsequently, the significant phenomenon of autapse-induced multiple coherence resonances is discovered. Moreover, the phenomenon of multiple coherence resonances can emerge at a broad parameter range of autaptic strength and autaptic delay.

We study the quantum transport through a mesoscopic AB ring with three leads. An exact solution for the quantum transport is obtained and it is shown that the transmitted currents j₁ and j₂ in the outgoing leads are modulated by the AB phase respectively and oscillate with the magnetic flux. We demonstrate that the corresponding probability currents I₁, I₂ and I₃ in the three arms l₁, l₂ and l₃ also oscillate with the magnetic flux Φ_AB for the cases l₁=l₂=l₃=L and l₁=L, l₂=l₃=2L.

We calculate the vacuum averages of the energy–momentum tensor associated with a massless left-handed spinor fields due to magnetic fluxes on idealized cosmic string spacetime. In this analysis three distinct configurations of magnetic fields are considered: (i) a homogeneous field inside the tube, (ii) a magnetic field proportional to 1/r, and (iii) a cylindrical shell with δ-function. In these three cases the axis of the infinitely long tubes of radius R coincides with the cosmic string. In order to proceed with these calculations we explicitly obtain the Euclidean Feynman propagators associated with these physical systems. As we shall see, these propagators possess two distinct parts. The first are the standard ones, i.e. corresponding to the spinor Green's functions associated with the massless fermionic fields on the idealized cosmic string spacetime with a magnetic flux running through the line singularity. The second parts are new, they are due to the finite thickness of the radius of the tubes. As we shall see these extra parts provide relevant contributions to the vacuum averages of the energy–momentum tensor.

The classical and the quantum expressions of the energy of the electromagnetic radiation are compared. This comparison shows that, contrary to the commonly expected, the dependency of the energy $𝜀$ of the photon with respect to the frequency $\nu$ on the Einstein–Planck relation $𝜀=h\nu$ is obtainable from classical electrodynamics, a fact that may provide a new historic perspective of the birth of quantum mechanics. It is suggested that the photon is a composite particle, constituted by quanta of electric and magnetic field fluxes maybe in an entangled state — being these two quanta either real or only as pseudo particles. It is also suggested a modification on the de Broglie’s fusion principle for the photon for the specific case in consideration.

In this paper, we have studied Kaluza–Klein Cosmological Model with strange-quark-matter in Lyra Geometry. To determine the solution of the field equation, we have assumed that scalar expansion $𝜃$ is proportional to shear scalar ${\sigma }^2$ which leads to $A_1={(A_2)}^r$, where $A_1$, $A_2$ are metric potentials and $r$ is arbitrary constant. The cosmological parameters are investigated with the help of equation of state strange-quark-matter (SQM), which is $p=\frac{\rho -4B_c}{3}$, where $B_c$ is Bag constant. We compared the results of general General relativity (GR) and scalar-tensor theory and also discussed the behaviors of some physical parameters.