Trapped surfaces, O(3) symmetry, and a generalization of Bjorken flow

by Steven Gubser (Princeton University)

Tuesday 20 Jul 2010, 14:00 → 15:00 Europe/Zurich

TH Theory Conference Room (CERN)

In attempts to understand entropy produced in collisions of gravitational shock waves in anti-de Sitter space, trapped surfaces stand as the simplest tool for obtaining analytical estimates. A straight forward comparison with heavy ion collisions at top RHIC energies shows remarkably close agreement between data-driven estimates of entropy production in central collisions and the entropy bound provided by trapped surfaces. The trapped surface estimates indicate faster scaling with beam energy than are generally expected as one passes to LHC energies. The simplest trapped surfaces have an O(3) symmetry which is part of the conformal group of four-dimensional Minkowski space. This same O(3) symmetry can be used to find a deformation of Bjorken flow in which the fluid expands radially as well as along the beam axis. An exact solution to the Navier-Stokes equation can be found for any value of the shear viscosity which respects the O(3) symmetry.