International Journal of Modern Physics B

Quantum phenomena have become directly observable with the development of advanced techniques such as coherent field-emission electron beams, sensitive detectors, and microlithography. Examples are the single-electron build-up of an interference pattern, which contains, as R. Feynman describes in his textbook, the heart of quantum mechanics, and the Aharonov–Bohm (AB) effect, which indicates the physical significance of gauge fields. Using the AB effect, i.e., the fundamental principle behind the interaction of an electron wave with electromagnetic fields, new ways to directly observe previously unobservable microscopic quantum objects and phenomena were developed by detecting the phase of electrons.

The ground-state energy density of an interacting dilute Bose gas system is studied in the canonical transformation scheme. It is shown that the transformation scheme enables us to calculate a higher order correction of order na³ in the particle depletion and ground-state energy density of a dilute Bose gas system, which corresponds to the density fluctuation resulting from the excited states. Considering a two-body interaction only, the coefficient of the na³ term is shown to be 2(π-8/3) for the particle depletion, and 16(π-8/3) for the ground-state energy density.

The nonlinear electromagnetic surface waves in waveguide structure which contains photosensitive semiconductor layer and left-handed material (LHM) layer have been studied. The effects of light intensity and the LHM on the dispersion of electromagnetic surface waves have been investigated. It has been noticed that, as a result of the foundation of LHM layer in the structure, both forward and backward electromagnetic surface waves exist in the waveguide. It has also been shown that the photosensitive semiconductor layer controls the propagation characteristics of the electromagnetic surface waves.

The power flow of the nonlinear surface waves has also been examined. It has been found that the majority of the electromagnetic surface waves propagate in the forward direction.

Energy levels of an impurity atom and its binding energy in a quantum dot with electron–phonon interactions are obtained by the second-order Rayleigh–Schrodinger perturbation theory. The energy correction is expressed as a function of the temperature, the applied magnetic field, and the effective confinement length of the quantum dot. We apply our calculations to GaAs.

The influence of nanosecond laser impulse irradiation on the magneto-optical properties of multilayer film nanostructures Bi–SiC–TbFe–SiC, SiC–TbFe–SiC, SiC–Tb–Au–Fe–SiC, and phthalocyanine dye–bismuth–phthalocyanine dye was investigated. It was shown that this irradiation causes the injection of spin-polarized electrons from magnetic into nonmagnetic layers of the multilayer films. Nonequilibrium magnetization arising in nonmagnetic layers leads to the change of magneto-optical characteristics. The voltage induced by laser irradiation can also produce a directed drift of Bi ions toward the laser beam action.

We study the uncertainty relations between photon number and canonical phase of a multilevel system. All the relevant quantities can be sampled directly from the measured phase-dependent quadrature distribution. Some comments are made on the extension of these relations to the case where the Hilbert space is of infinite dimension. We describe its theoretical basis and discuss its practical relevance, especially in comparison with already known results. Numerical calculations under specified initial conditions are presented.

In the present paper, we study a two-dimensional harmonic oscillator in a constant magnetic field in noncommuting space. We use the following Hamiltonian

The parameter λ expresses the presence of the magnetic field. We find the exact propagator of the system and the time evolution of the basic operators. We prove that the system is equivalent to a two-dimensional system where the operators of momentum and coordinates of the second dimension satisfy a deformed commutation relation . The deformation parameter, μ, depends on λ and θ, and is independent of the Hamiltonian. Finally, we investigate the thermodynamic properties of the system in Boltzmann statistics. We find the statistical density matrix and the partition function, which is equivalent to that of a two-dimensional harmonic oscillator with two deformed frequencies Ω₁ and Ω₂.

Spin transport properties of a mesoscopic superconductor/ferromagnetic (S/F) junctions of a quantum device are investigated. The thermoelectric voltage as a function of magnetic field oscillations for different heater currents has been calculated. The dependence shows that by increasing the heater current, the oscillation first disappears, and then remarkably reappears inverted compared to low heater current. Also, the value of the thermo-power increases with increasing value of the barrier strength. Our result shows that the degree of spin polarization of the current can be unambiguously determined using Andreev reflection. Our result agrees qualitatively with those in the literature.

The basic cytoskeletal transport in cells is achieved by two oppositely directed processive motor proteins, kinesin and dynein, walking along microtubules. Here, we offer a new view of the mechanism of the transport direction regulation by the intrinsic cell's electric fields that interact with kinks elicited in microtubules.