Cosmological solutions of supergravity in singular spaces

Abstract

We study brane-world solutions of five-dimensional supergravity in singular spaces. We exhibit a self-tuned four-dimensional cosmological constant when five-dimensional supergravity is broken by an arbitrary tension on the brane-world. The braneworld metric is of the FRW type corresponding to a cosmological constant Ω Λ =

Boundary inflation and the WMAP data

“…As χ is constant in this regime, the energy density of the boundary inflaton is constant leading to a constant detuning of the left brane tension. As already studied in [41], this leads to an accelerated phase with an exponential potential and power law inflation. More details about this power law inflation phase can be found in Ref.…”

“…In the framework of five-dimensional compactifications of M-theory [39,40], the moduli space approximation describes, through a four-dimensional effective action, a system of two branes of opposite tension embedded in a five-dimensional warped spacetime [41]. Besides the fields living on the positive tension brane (assumed to be our universe), the moduli associated with the position of the branes in the fifth dimension act as two non-minimally coupled scalar fields thereby leading to an effective biscalar-tensor theory of gravity [42,43,44,45,46,47,48,49].…”

Brane cosmology solutions with bulk scalar fields

“…The cosmology of this type of model with an exponential W has been considered elsewhere [7]. When C ≡ 0 the Friedmann equation (3.11) becomes ȧ a…”

“…For example, we could assume the bulk energy density has the form of a perfect fluid [6]. Alternatively, if the bulk potential energy resembles that of a supergravity theory, BPS solutions can be found [7].…”

The scalars of N=2, D=5 and attractor equations

“…This setup is a similar to the Hořava-Witten [6] theory, which was reduced to 5 dimensions in [7]. It has been considered by various groups [8,9,10,11], and our bulk& brane solution was used for cosmology in [12,13].…”