arXiv subjects

J. Rizos

Publications and source records attributed to J. Rizos.

39 records · Page 3Linked to original sources

arXiv1995

Dilatonic Black Holes in Higher Curvature String Gravity

We give analytical arguments and demonstrate numerically the existence of black hole solutions of the $4D$ Effective Superstring Action in the presence of Gauss-Bonnet quadratic curvature terms. The solutions possess non-trivial dilaton hair. The hair, however, is of ``secondary" type", in the sense that the dilaton charge is expressed in terms of the black hole mass. Our solutions are not covered by the assumptions of existing proofs of the ``no-hair" theorem. We also find some alternative solutions with singular metric behaviour, but finite energy. The absence of naked singularities in this system is pointed out.

hep-th↗

arXiv1994

On the existence of singularity-free solutions in quartic gravity

We study a general field theory of a scalar field coupled to gravitation through a quadratic Gauss-Bonnet term $ξ(ϕ)$$R_{GB}^2$. We show that, under mild assumptions about the function $ξ(ϕ)$, the classical solutions in a spatially flat FRW background include singularity - free solutions.

gr-qc↗

arXiv1993

Singularity-free cosmological solutions of the superstring effective action

We study the cosmological solutions of the one loop corrected superstring effective action, in a Friedmann-Robertson-Walker background, and in the presence of the dilaton and modulus fields. A particularly interesting class of solutions is found which avoid the initial singularity and are consistent with the perturbative treatment of the effective action.

hep-th↗