3,997 research outputs found
Stellar matter in the Quark-Meson-Coupling Model with neutrino trapping
The properties of hybrid stars formed by hadronic and quark matter in
-equilibrium are described by appropriate equations of state (EoS) in
the framework of the quark meson coupling (QMC) model. In the present work we
include the possibility of trapped neutrinos in the equation of state and
obtain the properties of the related hybrid stars. We use the quark meson
coupling model for the hadron matter and two possibilities for the quark matter
phase, namely, the unpaired quark phase and the color-flavor locked phase. The
differences are discussed and a comparison with other relativistic EoS is done.Comment: Reference added, accepted in PR
Quantum Vacuum in Hot Nuclear Matter - A Nonperturbative Treatment
We derive the equation of state for hot nuclear matter using Walecka model in
a nonperturbative formalism. We include here the vacuum polarisation effects
arising from the nucleon and scalar mesons through a realignment of the vacuum.
A ground state structure with baryon-antibaryon condensates yields the results
obtained through the relativistic Hartree approximation (RHA) of summing
baryonic tadpole diagrams. Generalization of such a state to include the
quantum effects for the scalar meson fields through the -meson
condensates amounts to summing over a class of multiloop diagrams. The
techniques of thermofield dynamics (TFD) method are used for the finite
temperature and finite density calculations. The in-medium nucleon and sigma
meson masses are also calculated in a self consistent manner. We examine the
liquid-gas phase transition at low temperatures ( 20 MeV), as well as
apply the formalism to high temperatures to examine for a possible chiral
symmetry restoration phase transition.Comment: 23 pages with 9 figure
Hot Nuclear Matter : A Variational Approach
We develop a nonperturbative technique in field theory to study properties of
infinite nuclear matter at zero temperature as well as at finite temperatures.
Here we dress the nuclear matter with off-mass shell pions. The techniques of
thermofield dynamics are used for finite temperature calculations. Equation of
state is derived from the dynamics of the interacting system in a self
consistent manner. The transition temperature for nuclear matter appears to be
around 15 MeV.Comment: 16 pages, IP/BBSR/91-3
Vacuum polarization effects in hyperon rich dense matter -- a nonperturbative treatment
We derive the equation of state (EOS) for electrically charge neutral dense
matter using Quantum Hadrodynamics (QHD) model. This is carried out in a
nonperturbative manner including quantum corrections for baryons through a
realignment of vacuum with baryon-antibaryon condensates. This yields the
results of relativistic Hartree approximation of summing over baryonic tadpole
diagrams. The quantum corrections from the scalar meson is also taken into
account in a similar way. This leads to a softening of the equation of state
for the hyperonic matter. The formalism also allows us to do a self consistent
calculation of the in-medium sigma meson mass. The effects of such quantum
corrections on the composition of charge neutral dense matter is considered.
The effect of the resulting EOS on the structure of the neutron stars is also
studied.Comment: 26 pages, Latex (ReVTeX style
A New Approach To Relativistic Gaussian Basis Functions: Theory And Applications
We present a new hybrid method to solve the relativistic Hartree-Fock-Roothan
equations where the one- and two-electron radial integrals are evaluated
numerically by defining the basis functions on a grid. This procedure reduces
the computational costs in the evaluation of two-electron radial integrals. The
orbitals generated by this method are employed to compute the ionization
potentials, excitation energies and oscillator strengths of alkali-metal atoms
and elements of group IIIA through second order many-body perturbation theor
and other correlated theories.Comment: RevTex (15 pages) one figur
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