197 research outputs found
Short time dynamics of molecular junctions after projective measurement
In this work, we study the short time dynamics of a molecular junction
described by Anderson-Holstein model using full-counting statistics after
projective measurement. The coupling between the central quantum dot (QD) and
two leads was turned on at remote past and the system is evolved to steady
state at time , when we perform the projective measurement in one of the
lead. Generating function for the charge transfer is expressed as a Fredholm
determinant in terms of Keldysh nonequilibrium Green's function in the time
domain. It is found that the current is not constant at short times indicating
that the measurement does perturb the system. We numerically compare the
current behaviors after the projective measurement with those in the transient
regime where the subsystems are connected at . The universal scaling for
high-order cumulants is observed for the case with zero QD occupation due to
the unidirectional transport at short times. The influences of electron-phonon
interaction on short time dynamics of electric current, shot noise and
differential conductance are analyzed
Dysfunctional signaling pathway for nitric oxide production in endothelial cells chronically exposed to high glucose or high fatty acids
Ph.DDOCTOR OF PHILOSOPH
Enhancing extraordinary transmission of light through a metallic nano slit with a nano cavity antenna
The extraordinary transmission of light through a nano slit in a metal film
is enhanced by introducing a nano cavity antenna formed by a nearby metallic
nano-strip over the slit opening. For a fixed wavelength, the width of the
metallic nano-strip should be chosen to make the horizontal
metal-insulator-metal waveguide of finite length resonant as a Fabry-Perot
cavity. When such a cavity antenna is used to enhance the transmission through
a non-resonant nano slit, the slit should be opened at a position with maximal
magnetic field in the horizontal resonant cavity. It is shown that an optimized
cavity antenna can enhance greatly the transmission of light through a
non-resonant nano slit (by about 20 times) or a resonant nano slit (by 124%).
The transmission spectrum of the nano slit can also be tuned by adjusting the
width of the metallic nano-strip. Such a transmission enhancement with a nano
cavity antenna is studied for the first time and the physical mechanism is
explained.Comment: 4 pages, 5 figure
Opposite spin accumulations on the transverse edges by the confining potential
We show that the spin-orbit interaction induced by the boundary confining
potential causes opposite spin accumulations on the transverse edges in a zonal
two-dimensional electron gas in the presence of external longitudinal electric
field. While the bias is reversed, the spin polarized direction is also
reversed. The intensity of the spin accumulation is proportional to the bias
voltage. In contrast to the bulk extrinsic and intrinsic spin Hall effects, the
spin accumulation by the confining potential is almost unaffected by impurity
and survives even in strong disorder. The result provides a new mechanism to
explain the recent experimental data.Comment: 5 pages, 6 figure
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