From large extra-dimensions to dark energy: an introduction to brane world models----中国科学院紫金山天文台

abstract

　　The idea that our four-dimensional universe (the brane) may be embedded in a higher dimensional universe (called the bulk) has attracted a lot of interest. Gravity is localized near the brane at low energies, even if the extra dimension is noncompact. A review is given of the classical geometry,dynamics and cosmological and astrophysical implications of the brane-world models. The field equations on the brane modify the field equations of general relativity in two ways: local 5-D effects are imprinted on the brane as a result of its embedding, and are significant at high energies; nonlocal effects arise from the 5-D Weyl tensor. The Weyl tensor transmits tidal (Coulomb),gravitomagnetic and gravitational wave effects to the brane from the 5-D nonlocal gravitational field. In astrophysics, local and nonlocal effects introduce fundamental changes to gravitational collapse, black hole solutions and for the propagations of the electromagnetic waves. The possibility of observationally testing the brane world model will also be considered in detail.