Chi-Shung Tang

Time-dependent transport via the generalized master equation through a finite quantum wire with an embedded subsystem

In this paper, we apply the generalized master equation to analyze time-dependent transport through a finite quantum wire with an embedded subsystem. The parabolic quantum wire and the leads with several subbands are described by a continuous model. We use an approach originally developed for a tight-binding description selecting the relevant states for transport around the bias-window defined around the values of the chemical potential in the left and right leads in order to capture the effects of the nontrivial geometry of the system in the transport. We observe a partial current reflection as a manifestation of a quasi-bound state in an embedded well and the formation of a resonance state between an off-set potential hill and the boundary of the system.

Coulomb interaction and transient charging of excited states in open nanosystems

We obtain and analyze the effect of electron-electron Coulomb interaction on the time-dependent current flowing through a mesoscopic system connected to biased semi-infinite leads. We assume the contact is gradually switched on in time and we calculate the time-dependent reduced density operator of the sample using the generalized master equation. The many-electron states (MES) of the isolated sample are derived with the exact-diagonalization method. The chemical potentials of the two leads create a bias window which determines which MES are relevant to the charging and discharging of the sample and to the currents, during the transient or steady states. We discuss the contribution of the MES with fixed number of electrons

Coherent electronic transport in a multimode quantum channel with Gaussian-type scatterers

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Time-dependent transport of electrons through a photon cavity

and we find that in the transient regime there are excited states more active than the ground state even for

Nonadiabatic current generation in a finite width semiconductor ring

N=1

Nonmagnetic control of spin flow: Generation of pure spin current in a Rashba-Dresselhaus quantum channel

. This is a dynamical signature of the Coulomb-blockade phenomenon. We discuss numerical results for three sample models: short one-dimensional chain, two-dimensional (2D) lattice, and 2D parabolic quantum wire.

Magnetic-field-influenced nonequilibrium transport through a quantum ring with correlated electrons in a photon cavity

Coherent electron transport through a quantum channel in the presence of a general extended scattering potential is investigated using a

Quantum magneto-electrodynamics of electrons embedded in a photon cavity

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Time-dependent magnetotransport in an interacting double quantum wire with window coupling

-matrix Lippmann\char21{}Schwinger approach. The formalism is applied to a quantum wire with Gaussian type scattering potentials, which can be used to model a single impurity, a quantum dot or more complicated structures in the wire. The well known dips in the conductance in the presence of attractive impurities are reproduced. A resonant transmission peak in the conductance is seen as the energy of the incident electron coincides with an energy level in the quantum dot. The conductance through a quantum wire in the presence of an asymmetric potential is also shown. In the case of a narrow potential parallel to the wire we find that two dips appear in the same subband which we ascribe to two quasi bound states originating from the next evanescent mode.

Coherent transient transport of interacting electrons through a quantum waveguide switch

We use a non-Markovian master equation to describe the transport of Coulomb-interacting electrons through an electromagnetic cavity with one quantized photon mode. The central system is a finite-parabolic quantum wire that is coupled weakly to external parabolic quasi-one-dimensional leads at