Brane-World Cosmological Perturbations

The standard cosmological model, based on general relativity with aninflationary era, is very effective in accounting for a broad range of observedfeatures of the universe. However, the ongoing puzzles about the nature of darkmatter and dark energy, together with the problem of a fundamental theoreticalframework for inflation, indicate that cosmology may be probing the limits ofvalidity of general relativity. The early universe provides a testing groundfor theories of gravity, since gravitational dynamics can lead tocharacteristic imprints on the CMB and other cosmological observations.Precision cosmology is in principle a means to constrain and possibly falsifycandidate quantum gravity theories like M theory. Generalized Randall-Sundrumbrane-worlds provide a phenomenological means to test aspects of M theory. Ioutline the 1+3-covariant approach to cosmological perturbations in thesebrane-worlds, and its application to CMB anisotropies.Comment: Based on a talk at the Brane-world Gravity Workshop, Yukawa Institute, Jan 2002. 17 pages, 4 figure