89 research outputs found
Superconducting Accelerating RF-Structure Stability at a High Energy Level from the Point of View of Thermal Balance
Quadratic solitons as nonlocal solitons
We show that quadratic solitons are equivalent to solitons of a nonlocal Kerr
medium. This provides new physical insight into the properties of quadratic
solitons, often believed to be equivalent to solitons of an effective saturable
Kerr medium. The nonlocal analogy also allows for novel analytical solutions
and the prediction of novel bound states of quadratic solitons.Comment: 4 pages, 3 figure
Electron correlation effects and magnetic ordering at the Gd(0001) surface
Effects of electron correlation on the electronic structure and magnetic
properties of the Gd(0001) surface are investigated using of the full-potential
linearized augmented plane wave implementation of correlated band theory
("LDA+U"). The use of LDA+U instead of LDA (local density approximation) total
energy calculations produces the correct ferromagnetic ground state for both
bulk Gd and the Gd surface. Surface strain relaxation leads to an 90 %
enhancement of the interlayer surface-to-bulk effective exchange coupling.
Application of a Landau-Ginzburg type theory yields a 30 % enhancement of the
Curie temperature at the surface, in very good agreement with the experiment.Comment: revised version: minor typos correcte
Cosmological consequences of particle creation during inflation
Particle creation during inflation is considered. It could be important for
species whose interaction is of gravitational strength or weaker. A complete
but economical formalism is given for spin-zero and spin-half particles, and
the particle abundance is estimated on the assumption that the particle mass in
the early universe is of order the Hubble parameter . It is roughly the same
for both spins, and it is argued that the same estimate should hold for higher
spin particles in particular the gravitino. The abundance is bigger than that
from the usual particle collision mechanism if the inflationary energy scale is
of order , but not if it is much lower.Comment: 17 pages, no Figure
(Non)-singular brane-world cosmology induced by quantum effects in d5 dilatonic gravity
5d dilatonic gravity (bosonic sector of gauged supergravity) with non-trivial
bulk potential and with surface terms (boundary cosmological constant and trace
anomaly induced effective action for brane quantum matter) is considered. For
constant bulk potential and maximally SUSY Yang-Mills theory (CFT living on the
brane) the inflationary brane-world is constructed. The bulk is singular
asymptotically AdS space with non-constant dilaton and dilatonic de Sitter or
hyperbolic brane is induced by quantum matter effects. At the same time,
dilaton on the brane is determined dynamically. This all is natural realization
of warped compactification in AdS/CFT correspondence. For fine-tuned toy
example of non-constant bulk potential we found the non-singular dilatonic
brane-world where bulk again represents asymptotically AdS space and de Sitter
brane (inflationary phase of observable Universe) is induced exclusively by
quantum effects. The radius of the brane and dilaton are determined
dynamically. The analytically solvable example of exponential bulk potential
leading to singular asymptotically AdS dilatonic bulk space with de Sitter (or
hyperbolic) brane is also presented.In all cases under discussion the gravity
on the brane is trapped via Randall-Sundrum scenario. It is shown that
qualitatively the same types of brane-worlds occur when quantum brane matter is
described by dilaton coupled spinors.Comment: LaTeX file 28 pages and two eps files, few misprints are correcte
Estimating Non-Flow Effects in Measurements of Anisotropic Flow of Protons with the HADES Experiment at GSI
Using δ18O as a Tracer of the Formation of Water Masses in the Laptev Sea. Part 1. Quantification of Ice Formation and Melting
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