Thin-shell in F(R) Theories. Presentación oral (co-autora).

EIROA, ERNESTO F.; FIGUEROA AGUIRRE, GRISELDA

La Falda, Córdoba

Congreso; Grav15; 2015

The attempts to understand and explain the cosmic acceleration of our universe result in many theories, being the most common ones those that use the concept of dark energy. However, they are not the only ones. Modifications of general relativity as the source of such acceleration, instead of exotic fluids, have been considered in order to explain it, highlighting in particular F(R) gravity models. These theories can be also used to analyse the behaviour of thin shells of matter. Thin-shell is a flexible formalism which allows to match different solutions onto a hyper-surface. For doing so, it is required junction conditions, which are more restrictive outside the general relativity, imposing requisites onto the scalar curvature R. This result in the fact that, in F(R) theories, the scalar curvature R never can be discontinuous; and only an exceptional case, for quadratic F(R) theories, is allowed. Otherwise, matched solutions will not be solutions of F(R) theories unless variables such as energy density or pressure fulfil quite restrictive conditions. We review these issues as well as the general aspects of the F(R) theories applied to thin-shells that had been studied recently.