Elastic Transient Energy Transport and Energy Balance in a Single-Level Quantum Dot System

Abstract

The decay of ThC (212Bi) to ThC' (212Po) has been studied by coincidence techniques and those gamma radiations emitted from the 21zPo nucleus have been distinguished from other gamma rays in the thorium decay series. An estimate of intensities has enabled the assignment of multipole orders to some transitions. The branching ratio of 212Bi and the half-life of the ground state of 212Po were re-measured.

Wavelet analysis of quantum transient transport in a quantum dot

“…1 Many computational works have also been performed, and found that the time-dependent currents through nanoscale systems often oscillate around the value of the stationary current after sudden switching-on of voltage. [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Such current oscillations decay with time and then the systems reach the steady states. This non-steady phenomenon, which often emerges in the case of a weak coupling between an electrode and a scattering region, is a consequence of roundtrip motions of electrons between them.…”

“…This non-steady phenomenon, which often emerges in the case of a weak coupling between an electrode and a scattering region, is a consequence of roundtrip motions of electrons between them. [7][8][9][10][12][13][14] This roundtrip motion originates from the interference between electrons in the scattering region before applying the voltage and electrons in the electrodes after applying voltage.…”

“…[5][6][7][8][9][10][11][12][13][14]18 For this approximation, to be valid, the time scale characterizing the current relaxation must be much longer than the rise time of the applied voltage. While the current relaxation time is roughly determined by the dwell time, i.e., the time that an electron spends in the scattering region, the dwell time generally decreases more with the downsizing of the nano-scale devices.…”

“…Our simulations of the time-dependent currents are based on non-equilibrium Green's function (NEGF) formalism within wide band limit (WBL) approximation. [5][6][7][8][9][10] To obtain systematic understanding, we have performed wavelet analysis on the calculated timedependent currents, and show that the wavelet spectra of the transient currents mainly consist of two components. It depends on the switching speed which of the two is dominant in determining the transient current behavior.…”

“…[5][6][7][8][9][10] The NEGF method as well as other methods [15][16][17][18][19] is applicable to nano-scale systems driven by the time-dependent voltage as shown in Fig. 1(b).…”