9,645 research outputs found
Products of rough finite state machines
In this paper, we introduce the concept of several products of rough finite
state machines. We establish their relationships through coverings and
investigate some algebraic properties for these products
Hot and Dense Hadron Gas (HG): A New Excluded-volume approach
We formulate a thermodynamically consistent equation of state (EOS), based on
excluded-volume approach, for a hot, dense hadron gas (HG). We calculate
various thermodynamical quantities of HG and various hadron ratios and compare
our model results with the results of other excluded-volume models and
experimental data. We also calculate various transport coefficients such as
etc. and compare them with other HG model results. Furthermore, we
test the validity of our model in getting the rapidity spectra of various
hadrons and the effect of flow on them is investigated by matching our
predictions with the experimental data.Comment: 5 pages, 4 figures, To be published in proceedings of QGP Meet-2012
held at VECC, Kolkata, Indi
Magnetic Susceptibility of NiO Nanoparticles
Nickel oxide nanoparticles of different sizes are prepared and characterized
by x-ray diffraction and transmission electron microscopy. A.C. susceptibility
measurements as a function of temperature are carried out for various particle
sizes and frequencies. We find that the behavior of the system is spin glass
like.Comment: 16 pages, 5 figure
Paramagnetic to Superparamagnetic Transition in Ni(OH)_2 Nanoparticles
We report the temperature and field dependence of dc magnetization on sol-gel
prepared nanoparticles of Ni(OH)_2. At higher temperature the system is found
to behave as a paramagnet while we find evidence for superparamagnetic blocking
at low temperature. The system shows a paramagnet-superparamagnet transition
and we discuss the underlying mechanism.Comment: 4 pages, 7 figures, a floating reference remove
Further Evidences for Spin Glass like behavior in NiO nanoparticles
Nickel oxide nanoparticles are prepared by a sol gel method and characterized
by x-ray diffraction and transmission electron microscope. Here we present
measurements on temperature and field dependence of magnetization and time
dependence of thermoremanent magnetization. Our conclusion based on these
measurements is that the system shows spin glass like behavior.Comment: 5 pages, 3 figure
Improved transfer efficiency with pulsed atom transfer between two magneto-optical traps
In our double magneto-optical trap (MOT) setup containing a vapor chamber MOT
(VC-MOT) and an ultra high vacuum MOT (UHV-MOT) for Rb atoms, we find
that transfer of atoms from VC-MOT to UHV-MOT can be enhanced by employing a
pulsed VC-MOT loading followed by a pulsed push beam, as compared to that
obtained by focusing a continuous wave (CW) push beam on a continuously loaded
VC-MOT. By choosing appropriately the VC-MOT duration and push beam duration,
the number of atoms in UHV-MOT was 3-times the number obtained with a
continuous VC-MOT and a CW push beam of optimized power. The processes
affecting the pulsed transfer have been studied.Comment: 10 pages, 4 figure
Coherent Lateral Motion of Penumbral Filaments during X-class Flare
The high-resolution pictures of the solar photosphere from space based 50 cm
Solar Optical Telescope (SOT) on-board Hinode spacecraft, are now routinely
observed. Such images of a delta-sunspot in NOAA 10930 were obtained by Hinode
during 13 December 2006 while a X-class flare occurred in this active region.
Two bright ribbons were visible even in white light and G-band images apart
from chromospheric Ca II H images. We register the sunspot globally using
cross-correlation technique and analyse local effects during flare interval. We
find that during flare the penumbral filaments show lateral motion. Also, we
locate two patches, one in either polarity, which show converging motion
towards the polarity inversion line (PIL). In Ca II H images we find kernel
with pre-flare brightening which lie along the PIL.Comment: 4 pages (ASP style), 2 figures, for the proceedings of "Hinode-3:The
third Hinode Science Meeting" Toky
Description of Hot and Dense Hadron Gas Properties in a New Excluded-Volume model
A new equation of state for a hot and dense hadron gas (HG) is obtained where
the finite hard-core size of baryons has been incorporated in a
thermodynamically consistent formulation of excluded volume correction. Our
model differs from other existing approaches on the following points. We assign
a hard-core volume only to each baryon and mesons though possess a small volume
but they can fuse and interpenetrate into one another. Use of the full quantum
statistics is made in obtaining the grand canonical partition function where
excluded-volume correction has been incorporated by explicitly integrating over
volume. We thus find that the new model works even for the cases of extreme
temperatures and/or densities where most of other approaches fail. The model
does not violate causality even at extreme densities. The temperature and
density dependence of various thermodynamical quantities, e.g. pressure, baryon
density, entropy and energy density compare well with the results of other
microscopic HG models. After suitable parametrization of the centre-of-mass
energy in terms of temperature and baryon chemical potential, we explore some
new freeze-out criteria which exhibit full independence of the collision energy
and of the structures of the colliding nuclei. We further demonstrate the
suitability of our model in explaining various experimental results of the
multiplicity-ratios of various particles and their antiparticles. Finally, we
use our excluded-volume model to obtain the transport behaviour of the hot
and/or dense HG such as shear viscosity to entropy ratio, speed of sound etc.
and compare the results with earlier calculations.Comment: 34 pages, 25 figures, 1 tabl
On Locating the Critical End Point in QCD Phase Diagram
We use the available two different self-consistent formulations of
quasiparticle models and extend their applications for the description of quark
gluon plasma (QGP) at non-vanishing baryon chemical potentials. The
thermodynamical quantities calculated from these models are compared with the
values obtained from lattice simulations and a good agreement between
theoretical calculations and lattice QCD data suggests that the values of the
parameters used in the paper are consistent. A new equation of state (EOS) for
a gas of extended baryons and pointlike mesons is presented here which
incorporates the repulsive hard-core interactions arising due to geometrical
size of baryons. A first order deconfining phase transition is constructed
using Gibb's equilibrium criteria between the hadron gas EOS and quasiparticle
model EOS for the weakly interacting quark matter. This leads to an interesting
finding that the phase transition line ends at a critical end point beyond
which a crossover region exists in the phase diagram.Comment: 4 pages, 1 figure, talk given by P. K. Srivastava at 6th
ICPAQGP-2010, Goa, India (Dec. 06-10, 2010). Submitted to Nuclear Physics
Upsilon suppression at energies available at the BNL Relativistic Heavy Ion Collider and at the CERN Large Hadron Collider in a modified color screening scenario
The suppression of heavy quarkonia e.g. , etc. is
considered as a suitable probe to identify the nature of the matter created in
heavy ion collisions. Recently we have presented a modified colour screening
model for suppression in the quark gluon plasma (QGP) using
quasiparticle model as the equation of state. In this paper, we extend our
model to calculate the anomalous suppression of various states of
arising due to QGP medium alone. We obtain the suppression patterns of
different bottomonia states with respect to centrality at various available
collision energies and compare them with the available experimental data.Comment: 7 pages, 7 figures, Revised version accepted for publication in
Physical Review C. arXiv admin note: substantial text overlap with
arXiv:1208.479
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