Expanding extra dimension on a conformally flat thick brane
Muhammad Taufiqur Rohman, Triyanta, Agus Suroso, Jusak Sali Kosasih

Theoretical High Energy Physics Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung
Jalan Ganesha 10, Bandung 40132, Indonesia

Abstract

A conformal flat thick brane model with static and non-static warp factors is examined. The extra coordinate is assumed to expand according to \(b(t) = a(t)^\gamma\) where \(b(t)\) and \(a(t)\) are, respectively, the scale factors of the extra dimension and the brane, while \(\gamma\) can be a constant or a function of time. From the five-dimensional Einstein^s equation, the generalized Friedmann^s equation was obtained. In this research we consider two types of warp functions, the first is a function of the extra coordinate only, \(A(z)\), while the second is a function of the extra coordinate and the time, \(A(t, z)\). We obtained the scale factor solutions for both types of the warp functions for some cases. For the first type of warp function, we also identified that massless scalar field is localized on the thick brane. Considering a reverse process, warp factor solutions corresponding to the familiar forms of scale factor were obtained.

Keywords: conformally flat brane, thick brane, brane cosmology

Topic: Theoretical High Energy Physics