Cosmological Frontiers in Fundamental Physics - 2010

We describe recent progress on the quantum description of the Kerr black hole. Previous descriptions of black hole microstates have relied on the existence of near-horizon regions with conformal symmetry, and hence have only worked for extremal or supersymmetric black holes. We argue that the states of non-extremal black holes can also be understood in terms of a conformal symmetry, the difference being that this symmetry is not geometrically realized. Thus a Kerr black hole is an excited state of a conformal field theory. By making certain (natural) assumptions about the nature of this dual CFT we can compute its density of states. This gives a microscopic computation of the Bekenstein-Hawking entropy of a Kerr black hole with arbitrary mass and angular momentum.

Constraining primordial non-Gaussianity can offer a window into the early universe, and into testing the inflationary paradigm, which is fully complementary to the approach offered by Cosmic Microwave Background polarization. Large-scale structure and galaxy surveys have recently received renewed attention as a way to constrain primordial non-Gaussianity. I will review the potential and the limitations of this approach and highlight its complementarity to Cosmic Microwave Background observations.

The network of tests shows the LCDM cosmology is a good approximation to what actually happened, but that need not mean it has all the physics relevant to cosmology back to light element formation. I will review properties of galaxies that seem to be particularly difficult to understand within LCDM and might be pointing to still better physics.