4 research outputs found
Evaporation of a two-dimensional charged black hole
We construct a dilatonic two-dimensional model of a charged black hole. The
classical solution is a static charged black hole, characterized by two
parameters, and , representing the black hole's mass and charge. Then we
study the semiclassical effects, and calculate the evaporation rate of both
and , as a function of these two quantities. Analyzing this dynamical
system, we find two qualitatively different regimes, depending on the
electromagnetic coupling constant . If the latter is greater than a
certain critical value, the charge-to-mass ratio decays to zero upon
evaporation. On the other hand, for smaller than the critical value,
the charge-to-mass ratio approaches a non-zero constant that depends on
but not on the initial values of and .Comment: Latex, 30 pages, accepted for publication in Phys. Rev.
Spherically symmetric dissipative anisotropic fluids: A general study
The full set of equations governing the evolution of self--gravitating
spherically symmetric dissipative fluids with anisotropic stresses is deployed
and used to carry out a general study on the behaviour of such systems, in the
context of general relativity. Emphasis is given to the link between the Weyl
tensor, the shear tensor, the anisotropy of the pressure and the density
inhomogeneity. In particular we provide the general, necessary and sufficient,
condition for the vanishing of the spatial gradients of energy density, which
in turn suggests a possible definition of a gravitational arrow of time. Some
solutions are also exhibited to illustrate the discussion.Comment: 28 pages Latex. To appear in Phys.Rev.
Dynamics of charged viscous dissipative cylindrical collapse with full causal approach
The aim of this paper is to investigate the dynamical aspects of charged
viscous cylindrical source by using Misner approach. To this end, we have
considered the more general charged dissipative fluid enclosed by the
cylindrical symmetric spacetime. The dissipative nature of the source is due to
the presence of dissipative variables in the stress-energy tensor. The
dynamical equations resulting from such charged cylindrical dissipative source
have been coupled with the causal transport equations for heat flux, shear and
bulk viscosity, in the context of Israel-Steward theory. In this case, we have
the considered the Israel-Steward transportation equations without excluding
the thermodynamics viscous/heat coupling coefficients. The results are compared
with the previous works in which such coefficients were excluded and viscosity
variables do not satisfy the casual transportation equations.Comment: 16 Pages, no figures, accepted for publication in EPJ