Conductance peaks and gaps in single-electron device with the presence of electron-electron interaction - “Nonequilibrium green function approach”

Consider a single-electron transistor (SET) with a small size quantum dot (QD), where confined energy and the Coulomb interaction control the charges adding to QD. In this paper, a theoretical analysis of the relation between source-drain voltage and gate voltage has been done to define quantum-Coulomb blocked (and unblocked) diamonds for QD that has N electrons. An analytical equation for the conductance has been derived using the non-equilibrium Green function technique (NEGFT). Further, the effect of QD size and the tunnelling rate on conductance peaks and gaps have been investigated. Finally, the effect of gate voltage on conductance peaks and gaps with respect the quantum-Coulomb blocked regions has been analysed.

Phenomenological explanation of spontaneous polarisation and onset ferroelectric Phase transition in RbH2AsO4 (RDA) crystal

By applying two-time thermal dependent Zuberav’s statistical, retarded Green function approach and modified earlier simple PLCM model Hamiltonian by adding some extra terms into it, like third-order and fourth-order, phonon anharmonic interactions, direct spin-spin terms, extra spin-lattice terms, and four body interaction terms, for theoretical investigation of thermal dependent spontaneous polarization and ferroelectric phase transition in the first-order phase, of RbH2AsO4crystal. It undergoes a ferroelectric phase transition at 109.9K. With the help of Dyson’s equation in the Mean-Field Approximation (MFA), theoretical formulae are obtained for electrical permittivity, tangent delta, Cochran’s mode frequency, spontaneous polarization, and response function. Model values are fitted for the above physical parameters to obtain variations with temperature. A comparison of theoretical finding has been made with the experimental finding reported by Blinc et al [12], and Zolototrubov et al[8].

Conductivity Mechanism of Ion–DNA Interaction in Dilute Solution

In this paper, we propose an impurity scattering model of quasi-one-dimensional disordered system for ion–DNA interaction in dilute solution based on the density of state in non-periodic DNA. This disordered system is composed of cations and DNA, the hydrogen ions adsorbed on the surface of DNA with negative charges are considered as impurities. It is hydrogen ions in hydration layer that cause the variations of the density of state near the Fermi level. The classical theory describes the linear dependence of conductivity on concentration. By developing the Green function approach of ion–DNA interaction in the dilute solution, the quantum theory not only gives the linear part but also demonstrates the nonlinear part of the conductivity.

Fractional Schrödinger equation and anomalous relaxation: Nonlocal terms and delta potentials

We review and extend some results for the fractional Schrödinger equation by considering nonlocal terms or potential given in terms of delta functions. For each case, we have obtained the solution in terms of the Green function approach.

Conditions for the existence of peaks in the Sigma hypernucleus spectra

The (K-, π±) sigma hypernuclear spectrum is studied qualitatively in the Green function approach, using a solvable interaction model. The general features of the spectrum are explained. The necessary conditions for the existence of peaks in the spectrum are also studied. We show that the resonant peaks can be distinguished in the case of a real strong spin-orbit potential with a relatively weak Sigma to Lambda conversion.

Electromagnetic field quantization and quantum optical input-output relation for grating

A quantization scheme is developed for the radiation and higher order electromagnetic fields in one dimensional periodic, dispersive and absorbing dielectric medium. For this structure, the Green function is solved based on the plane wave expansion method, thus the photon operators, commutation relations and quantum Langevin equations are given and studied based on the Green function approach, moreover, the input-output relations are also derived. It is proved that this quantum theory can be reduced back to that of the predecessors’ study on the homogenous dielectric. Based on this method, we find that the transformation of the photon state through the lossy grating is non-unitary and that the notable non-unitary transformation can be obtained by tuning the imaginary part of the permittivity, we also discussed the excellent quantum optical properties for the grating which are similar to the classical optical phenomena. We believe our work is very beneficial for the control and regulation of the quantum light based on gratings.