3 research outputs found
Induced wormholes due to quantum effects of spherically reduced matter in large N approximation
Using one-loop effective action in large N and s-wave approximation we
discuss the possibility to induce primordial wormholes at the early Universe.
An analytical solution is found for self-consistent primordial wormhole with
constant radius. Numerical study gives the wormhole solution with increasing
throat radius and increasing red-shift function. There is also some indication
to the possibility of a topological phase transition.Comment: LaTeX file, 2 eps figures, 9 pages, few misprints are corrected,
numerics are change
Stationary vs. singular points in an accelerating FRW cosmology derived from six-dimensional Einstein-Gauss-Bonnet gravity
Six-dimensional Einstein-Gauss-Bonnet gravity (with a linear Gauss-Bonnet
term) is investigated. This theory is inspired by basic features of results
coming from string and M-theory. Dynamical compactification is carried out and
it is seen that a four-dimensional accelerating FRW universe is recovered, when
the two-dimensional internal space radius shrinks. A non-perturbative structure
of the corresponding theory is identified which has either three or one stable
fixed points, depending on the Gauss-Bonnet coupling being positive or
negative. A much richer structure than in the case of the perturbative regime
of the dynamical compactification recently studied by Andrew, Bolen, and
Middleton is exhibited.Comment: 9 pages, 20 figures, accepted in PL