2,107 research outputs found
Exponentially Accurate Semiclassical Tunneling Wave Functions in One Dimension
We study the time behavior of wave functions involved in tunneling through a
smooth potential barrier in one dimension in the semiclassical limit. We
determine the leading order component of the wave function that tunnels. It is
exponentially small in . For a wide variety of incoming wave packets,
the leading order tunneling component is Gaussian for sufficiently small
. We prove this for both the large time asymptotics and for moderately
large values of the time variable
Are there plasminos in superconductors?
Hot and/or dense, normal-conducting systems of relativistic fermions exhibit
a particular collective excitation, the so-called plasmino. We compute the
one-loop self-energy, the dispersion relation and the spectral density for
fermions interacting via attractive boson exchange. It is shown that plasminos
also exist in superconductors.Comment: 15 pages, 14 figures, revte
The brightness distribution of IRC +10216 at 11 microns
The brightness distribution of IRC +10216 at a wavelength of 11 microns was measured in detail using a spatial interferometer. This brightness distribution appears to have azimuthal symmetry; an upper limit of 1.1 may be set to the ellipticity at 11 microns if the object has a major axis oriented either along or perpendicular to the major axis of the optical image. The radial distribution shows both compact and extended emission. The extended component, which is due to thermal emission from circumstellar dust, contributes 91% of the total flux and has a 1/e diameter of 0.90 minutes. The tapered shape of this component is consistent with a l/r squared dust density dependence. The compact component is unresolved (less than 0.2 minutes in diameter) and represents emission from the central star seen through the circumstellar envelope
Spatial heterodyne interferometry of VY Canis Major's, alpha Orionis, alpha Scorpii, and R leonis at 11 microns
Using the technique of heterodyne interferometry, measurements were made of the spatial distribution of 11 micron radiation from four late type stars. The circumstellar shells surrounding VY Canis Majoris, alpha Orionis, and alpha Scorpii were resolved, whereas that of R Leonis was only partially resolved at a fringe spacing of 0.4 sec
Superadiabatic transitions in quantum molecular dynamics
We study the dynamics of a molecule’s nuclear wave function near an avoided crossing of two electronic energy levels for one nuclear degree of freedom. We derive the general form of the Schrödinger equation in the nth superadiabatic representation for all n є N. Using these results, we obtain closed formulas for the time development of the component of the wave function in an initially unoccupied energy subspace when a wave packet travels through the transition region. In the optimal superadiabatic representation, which we define, this component builds up monotonically. Finally, we give an explicit formula for the transition wave function away from the avoided crossing, which is in excellent agreement with high-precision numerical calculations
Reconfigurable quadruple quantum dots in a silicon nanowire transistor
We present a novel reconfigurable metal-oxide-semiconductor multi-gate
transistor that can host a quadruple quantum dot in silicon. The device consist
of an industrial quadruple-gate silicon nanowire field-effect transistor.
Exploiting the corner effect, we study the versatility of the structure in the
single quantum dot and the serial double quantum dot regimes and extract the
relevant capacitance parameters. We address the fabrication variability of the
quadruple-gate approach which, paired with improved silicon fabrication
techniques, makes the corner state quantum dot approach a promising candidate
for a scalable quantum information architecture
- …