92,442 research outputs found
The Stability of Noncommutative Scalar Solitons
We determine the stability conditions for a radially symmetric noncommutative
scalar soliton at finite noncommutivity parameter . We find an
intriguing relationship between the stability and existence conditions for all
level-1 solutions, in that they all have nearly-vanishing stability eigenvalues
at critical . The stability or non-stability of the system may then
be determined entirely by the coefficient in the potential. For
higher-level solutions we find an ambiguity in extrapolating solutions to
finite which prevents us from making any general statements. For these
stability may be determined by comparing the fluctuation eigenvalues to
critical values which we calculate.Comment: 12 pages, corrected typo
A Note on Cosmic (p,q,r) Strings
The spectrum of bound states of F- and D-strings has a distinctive
square-root tension formula that is hoped to be a hallmark of fundamental
cosmic strings. We point out that the Bogomol'nyi-Prasad-Sommerfield (BPS)
bound for vortices in supersymmetric Abelian-Higgs models also
takes the square-root form. In contrast to string theory, the most general
supersymmetric field theoretic model allows for strings, with three
classes of strings rather than two. Unfortunately, we find that there do not
exist BPS solutions except in the trivial case. The issue of whether there
exist non-BPS solutions which may closely resemble the square-root form is left
as an open question.Comment: 4 pages; v2: references adde
A hybrid computer program for the visual display of compensatory system model parameters
A hybrid computer identification program has been developed which determines and displays those parameter values of a model of the compensatory control system that existed over the last fifteen seconds of operation. These values are up-dated every 0.05 sec so that a visual display of the parameters appears to be continuous. Presently, a closed loop crossover model is being used as the compensatory system model with the parameters K and tau displayed, however, any suitable model could be used in its place
Cosmic Superstring Scattering in Backgrounds
We generalize the calculation of cosmic superstring reconnection probability
to non-trivial backgrounds. This is done by modeling cosmic strings as wound
tachyon modes in the 0B theory, and the spacetime effective action is then used
to couple this to background fields. Simple examples are given including
trivial and warped compactifications. Generalization to strings is
discussed.Comment: 12 pages, 2 figures; v2: references adde
Feynman-Jackson integrals
We introduce perturbative Feynman integrals in the context of q-calculus
generalizing the Gaussian q-integrals introduced by Diaz and Teruel. We provide
analytic as well as combinatorial interpretations for the Feynman-Jackson
integrals.Comment: Final versio
Fingolimod modulates microglial activation to augment markers of remyelination
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
Predictions for the Spatial Distribution of Gluons in the Initial Nuclear State
We make predictions for the t-differential cross section of exclusive vector
meson production (EVMP) in electron-ion collisions, with the aim of comparing
DGLAP evolution to CGC models. In the current picture for the high-energy
nucleus, nonlinear effects need to be understood in terms of low- gluon
radiation and recombination as well as how this leads to saturation. EVMP
grants experimental access to the edge region of the highly-boosted nuclear
wavefunction, where the saturation scale for CGC calculations becomes
inaccessible to pQCD. On the other hand, DGLAP evolution requires careful
consideration of unitarity effects. The existing photoproduction
data in ep collisions provides a baseline for these theoretical calculations.
Under different small- frameworks we obtain a measurable distinction in both
the shape and normalization of the differential cross section predictions.
These considerations are relevant for heavy ion collisions because the initial
state may be further constrained, thus aiding in quantitative study of the
quark-gluon plasma.Comment: 4 pages, 2 figures, 6th Hard Probes Conference 201
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