Equation for spectrum of electron states in a potential well with uneven bottom

A method is proposed to determine the spectrum of bound states of electron making a stationary motion in a three-dimensional quantum well with uneven bottom. It is shown that the problem of finding the energy eigenvalues is reduced to investigation of multichannel scattering of the particle from the internal part of potential. Equation for the energy, depending on the transmission and reflection amplitudes, is obtained. For illustration of application of the method to concrete systems, a three-dimensional asymmetric quantum well with uneven bottom is considered.     

Multichannel scattering of a particle in a quantum wire of cylindrical symmetry

The Schrödinger equation for a scattering particle in a quantum wire is considered. We discuss two geometrical forms of cross-section of the wire: the rectangular section and the cylindrical one. It is shown that scattering of the particle on an arbitrary potential V = V (x, y, z,), given in the wire, can be considered as a multichannel scattering, where the index of the channel coincides with the index which determines energy levels of the confined transverse motion of the particle. A method for determination of the amplitudes of transmission T _i and reflection R _i in the case of multichannel scattering is proposed. The case of two-channel scattering is considered in detail and a method for determination of the scattering amplitudes T ₁, T ₂ and R ₁, R ₂ is proposed.     

Thermodynamics of a n-p condensate in asymmetric nuclear matter

We study the neutron-proton pairing in nuclear matter as a function of isospin asymmetry at finite temperatures and the empirical saturation density using realistic nuclear forces and Brueckner-renormalized single particle spectra. Our computation of the thermodynamic quantities shows that, while the difference of the entropies of the superconducting and normal phases anomalously changes its sign as a function of temperature for arbitrary asymmetry, the grand canonical potential does not; the superconducting state is found to be stable in the whole temperature-asymmetry plane. The pairing gap completely disappears for density asymmetries exceeding alpha(c) = (rho(n)-rho(p))/rho approximately 0.11.     

Investigation of the temperature coefficient of the forbidden band energy of CdSe<Subscript>1−x</Subscript>S<Subscript>x</Subscript> semiconductor nanostructures

The dependence of the semiconductor forbidden band energy temperature coefficient on the sizes of CdSe_1?xS_x nanocrystals embedded in a silicate glass is investigated experimentally and theoretically. It is revealed that the temperature coefficient dependence on the sizes of nanocrystals has a maximum. This behavior is explained by the reduction of nanocrystalline inclusion sizes at heating, which occurs in view of the more strong expansion of the matrix.     

Fermi Surface Topology Signature on the High Harmonics Generation in Graphene-Like Nanostructure

Journal of Experimental and Theoretical Physics - The response of high harmonics of a laser field to the change of Fermi surface topology in graphene-like nanostructures during the process of the...     

Kubo formulas for relativistic fluids in strong magnetic fields

Magnetohydrodynamics of strongly magnetized relativistic fluids is derived in the ideal and dissipative cases, taking into account the breaking of spatial symmetries by a quantizing magnetic field. A complete set of transport coefficients, consistent with the Curie and Onsager principles, is derived for thermal conduction, as well as shear and bulk viscosities. It is shown that in the most general case the dissipative function contains five shear viscosities, two bulk viscosities, and three thermal conductivity coefficients. We use Zubarev’s non-equilibrium statistical operator method to relate these transport coefficients to correlation functions of the equilibrium theory. The desired relations emerge at linear order in the expansion of the non-equilibrium statistical operator with respect to the gradients of relevant statistical parameters (temperature, chemical potential, and velocity.) The transport coefficients are cast in a form that can be conveniently computed using equilibrium (imaginary-time) infrared Green’s functions defined with respect to the equilibrium statistical operator.     

Photonic band gap in 1D Photonic crystals with gradient profile of pitch and amplitude of modulation

The optical properties of one-dimensional photonic crystals with graded profile of pitch and that of the amplitude of modulation are studied theoretically. The development method, elaborated by the authors earlier, is applied. We show that there exist photonic band gaps in their transmission spectra, and, moreover, they have much wider bandwidth.     

Equation for the Landauer resitivity in the case of multichannel scattering

Generalization of the Landauer resistivity ρ _N ^L is given for the case of multichannel scattering of a particle by the system of nonoverlapped N random potentials, depending on x − x _i and y, which are localized near the points x _i (i = 1,2,…N). It is shown that in this case a new resistivity ρ _N ^S appears, which is a power function of N. A recurrent equation is obtained for definition of the Landauer resistivity ρ _N ^L .