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Institute for the Physics and Mathematics of the UniverseWPI

IPMU seminar

Date: November 10, 2008, 16:30 -
Place: Seminar Room at IPMU Prefab. B, Kashiwa Campus of the University of Tokyo
Speaker: Kazuya Koyama (Portsmouth)
Title: Modified gravity as an alternative to dark energy [PDF]
Abstract: The biggest problem in cosmology is explaining the recently observed accelerated expansion of the universe. Within the framework of General Relativity (GR), the acceleration originates from "dark energy". Alternatively, there could be no dark energy, but a large-distance modification to GR may account for the late-time acceleration of the universe. The simplest model is the DGP braneworld, which has the same number of parameters as the standard LCDM model. This model is seriously challenged by observations, and also faces theoretical problems. But it remains an important toy model for exploring modified gravity theories. I will review its properties, its confrontation with observations, and some of its possible generalizations.