Physics

Abstract:  "Wormholes" seem to describe ensemble averages of some kind, but in realistic models of holography, like AdS_4xS^7, it seems there isn't anything to average over, except, in some examples, a single integer N. Is "averaging over N" enough...

Abstract: Dwarf galaxies, despite (or perhaps because of) their small masses, are puzzles that challenge prevailing cosmological models. As the most common galaxies in the universe, they offer a powerful window into studying dark matter on the...

Abstract: We analyze axion and axio-dilaton wormholes in flat space and AdS. Wormholes with Dirichlet boundary conditions for the axion are generally off-shell. By working with fixed flux boundary conditions for the higher-form axion field and...

Abstract: Gently stir a fluid in a large box sitting still. This talk is about the behavior of turbulence that is generated. We report results of large numerical simulations of the Navier-Stokes equations in a triply periodic box---and compare the...

Abstract: Neutron stars and black holes represent the inevitable endpoints of stellar evolution for high-mass stars. Despite the apparent fine-tuning of the physical conditions necessary to produce them, neutron stars are abundant in the Galaxy. On...

Abstract: A brief discussion of a recent paper with Chang-Han Chen

Abstract: There is a longstanding dream of realizing large-N Yang-Mills theory in D = 3,4 as a theory of confining strings. So far, our knowledge of this putative string is restricted to low energies, where one can use an effective field theory...

Abstract: I will describe recent progress towards understanding the gravitational path integral in AdS_3 quantum gravity and its boundary interpretation. A central question is: which spacetime topologies should be included in the path integral, and...

Abstract: The uniqueness of the Kerr-de Sitter family of  black hole spacetimes as stationary solutions to the Einstein vacuum equations is a crucial ingredient to understanding the final states of positive cosmological constant universes, such as...