20,372 research outputs found
Microparticle impact sensor measures energy directly
Construction of a capacitor sensor consisting of a dielectric layer between two conductive surface layers and connected across a potential source through a sensing resistor permits measurement of energy of impinging particles without degradation of sensitivity. A measurable response is produced without penetration of the dielectric layer
Multicanonical Recursions
The problem of calculating multicanonical parameters recursively is
discussed. I describe in detail a computational implementation which has worked
reasonably well in practice.Comment: 23 pages, latex, 4 postscript figures included (uuencoded
Z-compressed .tar file created by uufiles), figure file corrected
Simulated-tempering approach to spin-glass simulations
After developing an appropriate iteration procedure for the determination of
the parameters, the method of simulated tempering has been successfully applied
to the 2D Ising spin glass. The reduction of the slowing down is comparable to
that of the multicanonical algorithm. Simulated tempering has, however, the
advantages to allow full vectorization of the programs and to provide the
canonical ensemble directly.Comment: 12 pages (LaTeX), 4 postscript figures, uufiles encoded, submitted to
Physical Review
Glassy behavior induced by geometrical frustration in a hard-core lattice gas model
We introduce a hard-core lattice-gas model on generalized Bethe lattices and
investigate analytically and numerically its compaction behavior. If
compactified slowly, the system undergoes a first-order crystallization
transition. If compactified much faster, the system stays in a meta-stable
liquid state and undergoes a glass transition under further compaction. We show
that this behavior is induced by geometrical frustration which appears due to
the existence of short loops in the generalized Bethe lattices. We also compare
our results to numerical simulations of a three-dimensional analog of the
model.Comment: 7 pages, 4 figures, revised versio
Grundstate Properties of the 3D Ising Spin Glass
We study zero--temperature properties of the 3d Edwards--Anderson Ising spin
glass on finite lattices up to size . Using multicanonical sampling we
generate large numbers of groundstate configurations in thermal equilibrium.
Finite size scaling with a zero--temperature scaling exponent describes the data well. Alternatively, a descriptions in terms of Parisi
mean field behaviour is still possible. The two scenarios give significantly
different predictions on lattices of size .Comment: LATEX 9pages,figures upon request ,SCRI-9
Laboratory Tests of Gravitational Physics Using a Cryogenic Torsion Pendulum
Progress and plans are reported for a program of gravitational physics
experiments using cryogenic torsion pendula undergoing large amplitude
torsional oscillation. The program includes a UC Irvine project to measure the
gravitational constant G and joint UC Irvine - U. Washington projects to test
the gravitational inverse square law at a range of about 10 cm and to test the
weak equivalence principle.Comment: 17 pages, 11 figures, contribution to the 10th Marcel Grossman
Conference Proceedings (Rio de Janeiro, July 20 - 26, 2003) - changed wording
in first paragraph of section
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