8 research outputs found
Analytic self-gravitating Skyrmions, cosmological bounces and AdS wormholes
We present a self-gravitating, analytic and globally regular Skyrmion
solution of the Einstein-Skyrme system with winding number w = 1, in presence
of a cosmological constant. The static spacetime metric is the direct product
RxS3 and the Skyrmion is the self-gravitating generalization of the static
hedgehog solution of Manton and Ruback with unit topological charge. This
solution can be promoted to a dynamical one in which the spacetime is a
cosmology of the Bianchi type-IX with time-dependent scale and squashing
coefficients. Remarkably, the Skyrme equations are still identically satisfied
for all values of these parameters. Thus, the complete set of field equations
for the Einstein-Skyrme-Lambda system in the topological sector reduces to a
pair of coupled, autonomous, nonlinear differential equations for the scale
factor and a squashing coefficient. These equations admit analytic bouncing
cosmological solutions in which the universe contracts to a minimum
non-vanishing size, and then expands. A non-trivial byproduct of this solution
is that a minor modification of the construction gives rise to a family of
stationary, regular configurations in General Relativity with negative
cosmological constant supported by an SU(2) nonlinear sigma model. These
solutions represent traversable AdS wormholes with NUT parameter in which the
only "exotic matter" required for their construction is a negative cosmological
constant.Comment: 8 pages, no figures. References added. Title slightly changed.
Clarifying comments about both the dynamical squashing and the wormhole have
been included. Version accepted for publication on PHYSICS LETTERS
Non-Singular Charged Black Hole Solution for Non-Linear Source
A non-singular exact black hole solution in General Relativity is presented.
The source is a non-linear electromagnetic field, which reduces to the Maxwell
theory for weak field. The solution corresponds to a charged black hole with
|q| \leq 2s_c m \approx 0.6 m, having metric, curvature invariants, and
electric field bounded everywhere.Comment: 3 pages, RevTe
Analytic Lifshitz black holes in higher dimensions
We generalize the four-dimensional R^2-corrected z=3/2 Lifshitz black hole to
a two-parameter family of black hole solutions for any dynamical exponent z and
for any dimension D. For a particular relation between the parameters, we find
the first example of an extremal Lifshitz black hole. An asymptotically
Lifshitz black hole with a logarithmic decay is also exhibited for a specific
critical exponent depending on the dimension. We extend this analysis to the
more general quadratic curvature corrections for which we present three new
families of higher-dimensional D>=5 analytic Lifshitz black holes for generic
z. One of these higher-dimensional families contains as critical limits the z=3
three-dimensional Lifshitz black hole and a new z=6 four-dimensional black
hole. The variety of analytic solutions presented here encourages to explore
these gravity models within the context of non-relativistic holographic
correspondence.Comment: 14 page