A late-accelerating universe with no dark energy - and a finite-temperature big bang

Brane-world models off. er the possibility of explaining the late acceleration of the universe via infra-red modifications to general relativity, rather than a dark energy field. However, one also expects ultra-violet modifications to general relativity, when high-energy stringy effects in the early universe begin to grow. We generalize the DGP brane-world model via an ultra-violet modi. cation, in the form of a Gauss-Bonnet term in the bulk action. The combination of infrared and ultra-violet modifications produces an intriguing cosmology. The DGP feature of late-time acceleration without dark energy is preserved, but there is an entirely new feature-there is no infinite-temperature big bang in the early universe. The universe starts with finite density and pressure, from a 'quiet' and 'sudden' curvature singularity.