English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We explore the possibilities of constructing bulk spacetimes in fivedimensions for warped braneworld models with a spatially flatFriedmann-Robertson-Walker (FRW) line element on the 3-brane and with atime-dependent extra dimension. Our first step in this direction involveslooking at the status of energy conditions when such a bulk line element isassumed. We check these conditions by analysing the relevant inequalities, forspecific functional forms (chosen to satisfy certain desirable features) of thewarp factor, the cosmological scale factor and the extra-dimensional scalefactor. Subsequently, we aim at obtaining solutions with different types ofbulk matter sources. We begin with a general analysis of the solution space ofnon-singular Randall-Sundrum type bulk models with an exponential warp factorand a chosen equation of state. Thereafter, we focus on three specific bulksources -- the ordinary scalar field, the Brans-Dicke scalar and the dilaton.In each case, we are able to solve the field equations and obtain desirablesolutions for which, we once again check the viability of the energyconditions. We also show how one can place branes in the bulk using thejunction conditions. The issue of resolution of the bulk singularities whichappear in our solutions, using standard methods, is also presented briefly. Insummary, we are able to demonstrate, that it is indeed possible to constructviable bulk spacetimes for warped cosmological braneworlds with a time-varyingextra dimension and with bulk matter satisfying the energy conditions.

Bulk spacetimes for cosmological braneworlds with a time--dependent extra dimension