36,925 research outputs found
The pion mass dependence of the nucleon form-factors of the energy momentum tensor in the chiral quark-soliton model
The nucleon form factors of the energy-momentum tensor are studied in the
large-Nc limit in the framework of the chiral quark-soliton model for model
parameters that simulate physical situations in which pions are heavy. This
allows for a direct comparison to lattice QCD results.Comment: 17 pages, 12 figure
Diffusive Radiation in One-dimensional Langmuir Turbulence
We calculate spectra of radiation produced by a relativistic particle in the
presence of one-dimensional Langmuir turbulence which might be generated by a
streaming instability in the plasma, in particular, in the shock front or at
the shock-shock interactions. The shape of the radiation spectra is shown to
depend sensitively on the angle between the particle velocity and electric
field direction. The radiation spectrum in the case of exactly transverse
particle motion is degenerate and similar to that of spatially uniform Langmuir
oscillations. In case of oblique propagation, the spectrum is more complex, it
consists of a number of power-law regions and may contain a distinct
high-frequency spectral peak. %at \omega=2\omega\pe \gamma^2. The emission
process considered is relevant to various laboratory plasma settings and for
astrophysical objects as gamma-ray bursts and collimated jets.Comment: 4 pages, 1 figure, accepted for Phys. Rev.
Rashba spin precession in quantum Hall edge channels
Quasi--one dimensional edge channels are formed at the boundary of a
two-dimensional electron system subject to a strong perpendicular magnetic
field. We consider the effect of Rashba spin--orbit coupling, induced by
structural inversion asymmetry, on their electronic and transport properties.
Both our analytical and numerical results show that spin--split quantum--Hall
edge channels exhibit properties analogous to that of Rashba--split quantum
wires. Suppressed backscattering and a long spin life time render these edge
channels an ideal system for observing voltage--controlled spin precession.
Based on the latter, we propose a magnet--less spin--dependent electron
interferometer.Comment: 7 pages, 6 figure
A CDCL-style calculus for solving non-linear constraints
In this paper we propose a novel approach for checking satisfiability of
non-linear constraints over the reals, called ksmt. The procedure is based on
conflict resolution in CDCL style calculus, using a composition of symbolical
and numerical methods. To deal with the non-linear components in case of
conflicts we use numerically constructed restricted linearisations. This
approach covers a large number of computable non-linear real functions such as
polynomials, rational or trigonometrical functions and beyond. A prototypical
implementation has been evaluated on several non-linear SMT-LIB examples and
the results have been compared with state-of-the-art SMT solvers.Comment: 17 pages, 3 figures; accepted at FroCoS 2019; software available at
<http://informatik.uni-trier.de/~brausse/ksmt/
Entropy Functions with 5D Chern-Simons terms
In this note we reconsider Sen's entropy function analysis for 5D
supergravity actions containing Chern-Simons terms. The apparent lack of gauge
invariance is usually tackled via a 4D reduction. Here we motivate how a
systematic 5D procedure also works. In doing so, it becomes important to
identify the correct 5D charges. In particular, we perform explicit
calculations for the black ring and 5D black hole. In the black ring analysis,
we find Chern-Simons induced spectral flow shifts emerging out of Sen's
formalism. We find that the entropy function nevertheless remains gauge
invariant and the resulting electric charges are identified as Page charges.
For the black hole too, 5D gauge invariance is confirmed. Our 5D analysis
enables us to fix a mismatch that arose in the electric charges of Goldstein
and Jena's 4D-reduced calculation. Finally we provide an interpretation for the
e^0 - p^0 exchange in the entropy function as an interpolation between black
hole and black ring geometries in Taub-NUT.Comment: 27 page
Variabilidade genética de Fusarium decemcellulare isolado de três diferentes sintomas em guaranazeiro (Paullinia cupana var. sorbilis).
O objetivo deste trabalho foi analisar a variabilidade entre isolados obtidos de diferentes genótipos de guaranazeiro e de diferentes sintomas.Resumo:57-2
Remarks on the notion of quantum integrability
We discuss the notion of integrability in quantum mechanics. Starting from a
review of some definitions commonly used in the literature, we propose a
different set of criteria, leading to a classification of models in terms of
different integrability classes. We end by highlighting some of the expected
physical properties associated to models fulfilling the proposed criteria.Comment: 22 pages, no figures, Proceedings of Statphys 2
Asymmetric Fermi superfluid in a harmonic trap
We consider a dilute two-component atomic fermion gas with unequal
populations in a harmonic trap potential using the mean field theory and the
local density approximation. We show that the system is phase separated into
concentric shells with the superfluid in the core surrounded by the normal
fermion gas in both the weak-coupling BCS side and near the Feshbach resonance.
In the strong-coupling BEC side, the composite bosons and left-over fermions
can be mixed. We calculate the cloud radii and compare axial density profiles
systemically for the BCS, near resonance and BEC regimes.Comment: 15 pages, 5 figure
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