127 research outputs found
Evolution of non-stationary pulses in a cold magnetized quark-gluon plasma
We study weakly nonlinear wave perturbations propagating in a cold
nonrelativistic and magnetized ideal quark-gluon plasma. We show that such
perturbations can be described by the Ostrovsky equation. The derivation of
this equation is presented for the baryon density perturbations. Then we show
that the generalized nonlinear Schr{\"o}dinger (NLS) equation can be derived
from the Ostrovsky equation for the description of quasi-harmonic wave trains.
This equation is modulationally stable for the wave number and
unstable for , where is the wave number where the group velocity
has a maximum. We study numerically the dynamics of initial wave packets with
the different carrier wave numbers and demonstrate that depending on the
initial parameters they can evolve either into the NLS envelope solitons or
into dispersive wave trains
Self-bound Interacting QCD Matter in Compact Stars
The quark gluon plasma (QGP) at zero temperature and high baryon number is a
system that may be present inside compact stars. It is quite possible that this
cold QGP shares some relevant features with the hot QGP observed in heavy ion
collisions, being also a strongly interacting system. In a previous work we
have derived from the QCD Lagrangian an equation of state (EOS) for the cold
QGP, which can be considered an improved version of the MIT bag model EOS.
Compared to the latter, our equation of state reaches higher values of the
pressure at comparable baryon densities. This feature is due to perturbative
corrections and also to non-perturbative effects. Here we apply this EOS to the
study of neutron stars, discussing the absolute stability of quark matter and
computing the mass-radius relation for self-bound (strange) stars. The maximum
masses of the sequences exceed two solar masses, in agreement with the recently
measured values of the mass of the pulsar PSR J1614-2230, and the corresponding
radii around 10-11 km
Chromoelectric fields and quarkonium-hadron interactions at high energies
We develop a simple model to study the heavy quarkonium-hadron cross section
in the high energy limit. The hadron is represented by an external electric
color field (capacitor) and the heavy quarkonium is represented by a small
color dipole. Using high energy approximations we compute the relevant cross
sections, which are then compared with results obtained with other methods. Our
calculations are presented in a pedagogical way accessible to undergraduate
students.Comment: To appear in Physical Review C, 24 pages, 10 eps figure
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