958 research outputs found
Transfer matrices for scalar fields on curved spaces
We apply Nelson's technique of constructing Euclidean fields to the case of
classical scalar fields on curved spaces. It is shown how to construct a
transfer matrix and, for a class of metrics, the basic spectral properties of
its generator are investigated. An application concerning decoupling of
non-convex disjoint region is given.Comment: 11 pages, no figur
Weakly screened thermonuclear reactions in astrophysical plasmas: Improving Salpeter's model
This paper presents a detailed study of the electron degeneracy and nonlinear
screening effects which play a crucial role in the validity of Salpeter's
weak-screening model. The limitations of that model are investigated and an
improved one is proposed which can take into account nonlinear screening
effects. Its application to the solar pp reaction derives an accurate screening
enhancement factor and provides a very reliable estimation of the associated
neutrino flux uncertanties.Comment: 23 RevTex pages + 4 ps figures. (No revision,just adding URL link).
Accepted for publication in Europ.Phys.J.A. See
http://link.springer.de/link/service/journals/10105/index.ht
Fingerprints of entangled states in reactions with rare isotopes
We study the presence of entangled states of nucleon pairs from nuclear
decays and in reactions with exotic nuclei, e.g., 11Li, or 6He. It is shown
that the fingerprints of entangled states in these subsystems are visible in
correlation measurements and can be accessed with present experimental
techniques. This shows that not only atomic and optical systems, but also
nuclear systems serve as important tools to obtain dichotomic outcomes for
tests of the Einstein-Podolsky-Rosen paradox.Comment: 13 pages, 3 figures, to be published in Journal of Physics
Binary hard-sphere fluids near a hard wall
By using the Rosenfeld density functional we determine the number density
profiles of both components of binary hard-sphere fluids close to a planar hard
wall as well as the corresponding excess coverage and surface tension. The
comparison with published simulation data demonstrates that the Rosenfeld
functional, both its original version and sophistications thereof, is superior
to previous approaches and exhibits the same excellent accuracy as known from
studies of the corresponding one-component system
ON A DYNAMICAL MODEL OF GLASSES
We analyze a simple dynamical model of glasses, based on the idea that each
particle is trapped in a local potential well, which itself evolves due to
hopping of neighbouring particles. The glass transition is signalled by the
fact that the equilibrium distribution ceases to be normalisable, and dynamics
becomes non-stationary. We generically find stretching of the correlation
function at low temperatures and a Vogel-Fulcher like behaviour of the terminal
time.Comment: 11 pages, 2 figures (available upon request
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