Tunneling Time Distribution by means of Nelson's Quantum Mechanics and Wave-Particle Duality

We calculate a tunneling time distribution by means of Nelson's quantum mechanics and investigate its statistical properties. The relationship between the average and deviation of tunneling time suggests the exsistence of ``wave-particle duality'' in the tunneling phenomena.Comment: 14 pages including 11 figures, the text has been revise

Spin dependent observable effect for free particles using the arrival time distribution

The mean arrival time of free particles is computed using the quantum probability current. This is uniquely determined in the non-relativistic limit of Dirac equation, although the Schroedinger probability current has an inherent non-uniqueness. Since the Dirac probability current involves a spin-dependent term, an arrival time distribution based on the probability current shows an observable spin-dependent effect, even for free particles. This arises essentially from relativistic quantum dynamics, but persists even in the non-relativistic regime.Comment: 5 Latex pages, 2.eps figures; discussions sharpened and references added; accepted for publication in Physical Review

Time of arrival through interacting environments: Tunneling processes

We discuss the propagation of wave packets through interacting environments. Such environments generally modify the dispersion relation or shape of the wave function. To study such effects in detail, we define the distribution function P_{X}(T), which describes the arrival time T of a packet at a detector located at point X. We calculate P_{X}(T) for wave packets traveling through a tunneling barrier and find that our results actually explain recent experiments. We compare our results with Nelson's stochastic interpretation of quantum mechanics and resolve a paradox previously apparent in Nelson's viewpoint about the tunneling time.Comment: Latex 19 pages, 11 eps figures, title modified, comments and references added, final versio

Crystal chemistry search of multiferroics with the stereochemically active lone pair

On the basis of our previous studies of magnetoelectric ordering of BiFeO3, TbMnO3, TbMn2O5 and BiMn2O5 we formulate the crystal chemistry criteria for the search of multiferroics and reveal potential multiferroics Pb2Cu(OH)4Cl2, Pb5Cr3F19, Mn(SeO3){\dot}H2O and BiPbSr2MnO6 each containing the ion with a lone pair.Comment: 4 pages, 8 figures,submitted to J Supercond Nov Mag

Beam spin asymmetry measurements of deeply virtual π0 production with CLAS12

The new experimental measurements of beam spin asymmetry were performed for the deeply virtual exclusive pi0 production in a wide kinematic region with the photon virtualities Q2 up to 6.6 GeV2 and the Bjorken scaling variable xB in the valence regime. The data were collected by the CEBAF Large Acceptance Spectrometer (CLAS12) at Jefferson Lab with longitudinally polarized 10.6 GeV electrons scattered on an unpolarized liquid-hydrogen target. Sizable asymmetry values indicate a substantial contribution from transverse virtual photon amplitudes to the polarized structure functions. The interpretation of these measurements in terms of the Generalized Parton Distributions (GPDs) demonstrates their sensitivity to the chiral-odd GPD ET, which contains information on quark transverse spin densities in unpolarized and polarized nucleons and provides access to the nucleon's transverse anomalous magnetic moment. Additionally, the data were compared to a theoretical model based on a Regge formalism that was extended to the high photon virtualities

Two-dimensional numerical simulation of the pulse response of a semi-insulating InGaAs:Fe photodetector

A calculation is described of the transient pulse response of a planar metal-semiconductor-metal photodetector consisting of Schottky contacts made to an active layer of semi-insulating InGaAs:Fe that is supported on an InP:Fe substrate. The simulation uses a two-dimensional, drift/diffusion calculation and includes external circuit elements. Realistic conditions are considered where the semi-insulating material is represented by a two-level compensation model with Fe as a deep acceptor and hole trap that compensates shallow n-type impurities. The calculated results are compared directly with experimental ones for micron-scale devices described in the literature. The calculation gives a microscopic picture of how trapping controls particularly the falling side of the transient response, and it also shows how the measured performance of the device can reflect the influence of typical external circuit elements.NRC publication: Ye

Simulation of the hole and current distributions in Si-Ge p-channel FETs with graded profiles

NRC publication: Ye

A comparison of the dc and rf characteristics of single and double InP/InGaAs heterojunction bipolar transistors

Peer reviewed: YesNRC publication: Ye