472,803 research outputs found
Tkachenko modes as sources of quasiperiodic pulsar spin variations
We study the long wavelength shear modes (Tkachenko waves) of triangular
lattices of singly quantized vortices in neutron star interiors taking into
account the mutual friction between the superfluid and the normal fluid and the
shear viscosity of the normal fluid. The set of Tkachenko modes that propagate
in the plane orthogonal to the spin vector are weakly damped if the coupling
between the superfluid and normal fluid is small. In strong coupling, their
oscillation frequencies are lower and are undamped for small and moderate shear
viscosities. The periods of these modes are consistent with the observed
~100-1000 day variations in spin of PSR 1828-11.Comment: 7 pages, 3 figures, uses RevTex, v2: added discussion/references,
matches published versio
Dynamics of Fractal Solids
We describe the fractal solid by a special continuous medium model. We
propose to describe the fractal solid by a fractional continuous model, where
all characteristics and fields are defined everywhere in the volume but they
follow some generalized equations which are derived by using integrals of
fractional order. The order of fractional integral can be equal to the fractal
mass dimension of the solid. Fractional integrals are considered as an
approximation of integrals on fractals. We suggest the approach to compute the
moments of inertia for fractal solids. The dynamics of fractal solids are
described by the usual Euler's equations. The possible experimental test of the
continuous medium model for fractal solids is considered.Comment: 12 pages, LaTe
Revivification of confinement resonances in the photoionization of @C endohedral atoms far above thresholds
It is discovered theoretically that significant confinement resonances in an
photoionization of a \textit{multielectron} atom encaged in carbon
fullerenes, A@C, may re-appear and be strong at photon energies far
exceeding the ionization threshold, as a general phenomenon. The reasons
for this phenomenon are unraveled. The Ne photoionization of the
endohedral anion Ne@C in the photon energy region of about a
thousand eV above the threshold is chosen as case study.Comment: 3 pages, 1 figure, Revtex
New Signals of Quark-Gluon-Hadron Mixed Phase Formation
Here we present several remarkable irregularities at chemical freeze-out
which are found using an advanced version of the hadron resonance gas model.
The most prominent of them are the sharp peak of the trace anomaly existing at
chemical freeze-out at the center of mass energy 4.9 GeV and two sets of highly
correlated quasi-plateaus in the collision energy dependence of the entropy per
baryon, total pion number per baryon, and thermal pion number per baryon which
we found at the center of mass energies 3.8-4.9 GeV and 7.6-10 GeV. The low
energy set of quasi-plateaus was predicted a long time ago. On the basis of the
generalized shock-adiabat model we demonstrate that the low energy correlated
quasi-plateaus give evidence for the anomalous thermodynamic properties inside
the quark-gluon-hadron mixed phase. It is also shown that the trace anomaly
sharp peak at chemical freeze-out corresponds to the trace anomaly peak at the
boundary between the mixed phase and quark gluon plasma. We argue that the high
energy correlated quasi-plateaus may correspond to a second phase transition
and discuss its possible origin and location. Besides we suggest two new
observables which may serve as clear signals of these phase transformations.Comment: 14 pages, 4 figures, new signals of QGP formation are suggeste
A note on the generalised Lie algebra sl(2)q
In a recent paper, V. Dobrev and A. Sudbery classified the highest-weight and
lowest-weight finite dimensional irreducible representations of the quantum Lie
algebra sl(2)_q introduced by V. Lyubashenko and A. Sudbery. The aim of this
note is to add to this classification all the finite dimensional irreducible
representations which have no highest weight and/or no lowest weight, in the
case when q is a root of unity. For this purpose, we give a description of the
enlarged centre.Comment: Latex2e, 7 page
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