Regular braneworlds with nonlinear bulk-fluids

Abstract

Abstract We construct a regular five-dimensional brane-world with localised gravity on a flat 3-brane. The matter content in the bulk is parametrised by an analog of a non-linear fluid with equation of state $$p=\gamma \rho ^\lambda $$ p = γ ρ λ between the ‘pressure’ p and the ‘density’ $$\rho $$ ρ dependent on the 5th dimension. For $$\gamma $$ γ negative and $$\lambda >1$$ λ > 1 , the null energy condition is satisfied and the geometry is free of singularities within finite distance from the brane, while the induced four-dimensional Planck mass is finite.