NBIA Gravity Seminar: Thomas Baumgarte

Speaker:Prof. Thomas Baumgarte, Bowdoin College

Title: Critical Phenomena in Gravitational Collapse

Abstract: 
Critical Phenomena, including the appearance of universal scaling laws and critical exponents in the vicinity of phase transitions, appear in different fields of physics and beyond.  Critical phenomena in gravitational collapse to black holes were first observed by Matt Choptuik about 30 years ago - a seminal discovery that launched an entire new field of research.  While many aspects of critical collapse are well understood in the context of spherical symmetry, much less is known for systems that break spherical symmetry.  In particular, this includes the perhaps most intriguing case, namely the collapse of vacuum gravitational waves.  In this talk I will discuss the appearance of scaling laws and self-similarity close to the onset of black hole formation.  I will review a number of attempts to reproduce early reports of these phenomena for the collapse of gravitational waves, leading up to results from current simulations.  Based on these recent results I will suggest how our notion of criticality may have to be generalized in order to account for these phenomena in the absence of spherical symmetry.