33,563 research outputs found
A nonlinear analysis for sloshing forces and moments on a cylindrical tank
Sloshing forces and moments on cylindrical tank - integration of nonlinear force equation
An approximate nonlinear analysis of the stability of sloshing modes under transla- tional and rotational excitation
Nonlinear analysis of sloshing mode stability under translational and rotational excitatio
Pulsation models for the roAp star HD 134214
Precise time-series photometry with the MOST satellite has led to
identification of 10 pulsation frequencies in the rapidly oscillating Ap (roAp)
star HD 134214. We have fitted the observed frequencies with theoretical
frequencies of axisymmetric modes in a grid of stellar models with dipole
magnetic fields. We find that, among models with a standard composition of
and with suppressed convection, eigenfrequencies of a
model with and a polar
magnetic field strength of 4.1kG agree best with the observed frequencies. We
identify the observed pulsation frequency with the largest amplitude as a
deformed dipole () mode, and the four next-largest-amplitude
frequencies as deformed modes. These modes have a radial quasi-node
in the outermost atmospheric layers (). Although the model
frequencies agree roughly with observed ones, they are all above the acoustic
cut-off frequency for the model atmosphere and hence are predicted to be
damped. The excitation mechanism for the pulsations of HD 134214 is not clear,
but further investigation of these modes may be a probe of the atmospheric
structure in this magnetic chemically peculiar star.Comment: 9 pages, 6 figures; accepted for publication in MNRA
Violation of the Leggett-Garg Inequality in Neutrino Oscillations
The Leggett-Garg inequality, an analogue of Bell's inequality involving
correlations of measurements on a system at different times, stands as one of
the hallmark tests of quantum mechanics against classical predictions. The
phenomenon of neutrino oscillations should adhere to quantum-mechanical
predictions and provide an observable violation of the Leggett-Garg inequality.
We demonstrate how oscillation phenomena can be used to test for violations of
the classical bound by performing measurements on an ensemble of neutrinos at
distinct energies, as opposed to a single neutrino at distinct times. A study
of the MINOS experiment's data shows a greater than violation over
a distance of 735 km, representing the longest distance over which either the
Leggett-Garg inequality or Bell's inequality has been tested.Comment: Updated to match published version. 6 pages, 2 figure
Effect of a Coulombic dot-lead coupling on the dynamics of a quantum dot
The effect of a Coulombic coupling on the dynamics of a quantum dot
hybridized to leads is determined. The calculation treats the interaction
between charge fluctuations on the dot and the dynamically generated image
charge in the leads. A formally exact solution is presented for a dot coupled
to a Luttinger liquid and an approximate solution, equivalent to treating the
lead dynamics within a random phase approximation, is given for a dot coupled
to a two- or three-dimensional metallic lead. The leading divergences arising
from the long-ranged Coulomb interaction are found to cancel, so that in the
two- and three-dimensional cases the quantum-dot dynamics is equivalent to that
obtained by neglecting both the dot-lead Coulomb coupling and the Coulomb
renormalization of the lead electrons, while in the one-dimensional case the
dot-lead mixing is enhanced relative to the non-interacting case. Explicit
results are given for the short-time dynamics.Comment: 8 pages, 2 figures, version as publishe
Comparison of Josephson vortex flow transistors with different gate line configurations
We performed numerical simulations and experiments on Josephson vortex flow
transistors based on parallel arrays of YBa2Cu3O(7-x) grain boundary junctions
with a cross gate-line allowing to operate the same devices in two different
modes named Josephson fluxon transistor (JFT) and Josephson fluxon-antifluxon
transistor (JFAT). The simulations yield a general expression for the current
gain vs. number of junctions and normalized loop inductance and predict higher
current gain for the JFAT. The experiments are in good agreement with
simulations and show improved coupling between gate line and junctions for the
JFAT as compared to the JFT.Comment: 3 pages, 6 figures, accept. for publication in Appl. Phys. Let
Entanglement at the boundary of spin chains near a quantum critical point and in systems with boundary critical points
We analyze the entanglement properties of spins (qubits) attached to the
boundary of spin chains near quantum critical points, or to dissipative
environments, near a boundary critical point, such as Kondo-like systems or the
dissipative two level system. In the first case, we show that the properties of
the entanglement are significantly different from those for bulk spins. The
influence of the proximity to a transition is less marked at the boundary. In
the second case, our results indicate that the entanglement changes abruptly at
the point where coherent quantum oscillations cease to exist. The phase
transition modifies significantly less the entanglement.Comment: 5 pages, 4 figure
- …