engleski

Tachyon with an inverse power-law potential in a braneworld cosmology

We study a tachyon cosmological model based on the dynamics of a 3-brane in the bulk of the second Randall–Sundrum model extended to more general warp functions. A well known prototype of such a generalization is the bulk with a selfinteracting scalar field. As a consequence of a generalized bulk geometry the cosmology on the observer brane is modified by the scale dependent four-dimensional gravitational constant. In particular, we study a power law warp factor which generates an inverse power-law potential $V\propto \varphi^{; ; -n}; ; $ of the tachyon field phiv. We find a critical power n cr that divides two subclasses with distinct asymptotic behaviors: a dust universe for $n>n_{; ; \rm cr}; ; $ and a quasi de Sitter universe for $0<n<n_{; ; \rm cr}; ; $ .

tachyon ; braneworld cosmology ; Randall–Sundrum model

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