1,018 research outputs found
QGP collective effects and jet transport
We present numerical simulations of the SU(2) Boltzmann-Vlasov equation
including both hard elastic particle collisions and soft interactions mediated
by classical Yang-Mills fields. We provide an estimate of the coupling of jets
to a hot isotropic plasma, which is independent of infrared cutoffs. In
addition, we investigate jet propagation in anisotropic plasmas, as created in
heavy-ion collisions. The broadening of jets is found to be stronger along the
beam line than in azimuth due to the creation of field configurations with
B_t>E_t and E_z>B_z via plasma instabilities.Comment: 4 pages, 5 figures. Presented at the 20th International Conference on
Ultra-Relativistic Nucleus-Nucleus Collisions: Quark Matter 2008 (QM2008),
Jaipur, India, 4-10 Feb 200
How Wide is the Transition to Deconfinement?
Pure SU(3) glue theories exhibit a deconfining phase transition at a nonzero
temperature, Tc. Using lattice measurements of the pressure, we develop a
simple matrix model to describe the transition region, when T > Tc. This model,
which involves three parameters, is used to compute the behavior of the 't
Hooft loop. There is a Higgs phase in this region, where off diagonal color
modes are heavy, and diagonal modes are light. Lattice measurements of the
latter suggests that the transition region is narrow, extending only to about
1.2 Tc. This is in stark contrast to lattice measurements of the renormalized
Polyakov loop, which indicates a much wider width. The possible implications
for the differences in heavy ion collisions between RHIC and the LHC are
discussed.Comment: v2: Minor changes in wording, references adde
A Weibel Instability in the Melting Color Glass Condensate
Based on hep-ph/0510121, we discuss further the numerical study of classical
SU(2) 3+1-D Yang-Mills equations for matter produced in a high energy heavy ion
collision. The growth of the amplitude of fluctuations as (where is a scale arising from the saturation of
gluons in the nuclear wavefunction) is shown to be robust over a wide range of
initial amplitudes that violate boost invariance. We argue that this growth is
due to a non-Abelian Weibel instability, the scale of which is set by a
dynamically generated plasmon mass. We find good agreement when we relate
to the prediction from kinetic theory.Comment: 8 pages, invited talk at Workshop on Quark Gluon Plasma
Thermalization, Vienna, August 10th-12th, 200
A survey on fuzzy fractional differential and optimal control nonlocal evolution equations
We survey some representative results on fuzzy fractional differential
equations, controllability, approximate controllability, optimal control, and
optimal feedback control for several different kinds of fractional evolution
equations. Optimality and relaxation of multiple control problems, described by
nonlinear fractional differential equations with nonlocal control conditions in
Banach spaces, are considered.Comment: This is a preprint of a paper whose final and definite form is with
'Journal of Computational and Applied Mathematics', ISSN: 0377-0427.
Submitted 17-July-2017; Revised 18-Sept-2017; Accepted for publication
20-Sept-2017. arXiv admin note: text overlap with arXiv:1504.0515
Two-point functions for SU(3) Polyakov Loops near T_c
We discuss the behavior of two point functions for Polyakov loops in a SU(3)
gauge theory about the critical temperature, T_c. From a Z(3) model, in mean
field theory we obtain a prediction for the ratio of masses at T_c, extracted
from correlation functions for the imaginary and real parts of the Polyakov
loop. This ratio is m_i/m_r = 3 if the potential only includes terms up to
quartic order in the Polyakov loop; its value changes as pentic and hexatic
interactions become important. The Polyakov Loop Model then predicts how
m_i/m_r changes above T_c.Comment: 5 pages, no figures; reference adde
A user-centric execution environment for <em>CineGrid</em> workloads
The abundance and heterogeneity of IT resources available, together with the ability to dynamically scale applications poses significant usability issues to users. Without understanding the performance profile of available resources users are unable to efficiently scale their applications in order to meet performance objectives. High quality media collaborations, like CineGrid, are one example of such diverse environments where users can leverage dynamic infrastructures to move and process large amounts of data. This paper describes our user-centric approach to executing high quality media processing workloads over dynamic infrastructures. Our main contribution is the CGtoolkit environment, an integrated system which aids users cope with the infrastructure complexity and large data sets specific to the digital cinema domain
Asymptotic integration of -order fractional differential equations
\noindent{\bf Abstract} We establish the long-time asymptotic formula of
solutions to the --order fractional differential equation
, , under some simple
restrictions on the functional coefficient , where is one of the fractional differential operators
,
and
. Here, designates
the Riemann-Liouville derivative of order . The asymptotic
formula reads as as for given ,
, where and represent the eventually small and eventually large solutions that
generate the solution space of the fractional differential equation
, .Comment: 16 page
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