Title:  "Why Might Primordial Gravitational Waves be Necessary?"

Abstract:  The recent breakthrough detection of primordial gravitational waves by the BICEP2 telescope confirms a longstanding prediction from the cosmic inflationary paradigm.  It is interesting the theories beyond the standard model of particle interactions, such as string theory generically predict modifications to Einsteins theory of general relativity that are left-right asymmetric (parity violating).  In this colloquium I provide a pedagogical discussion of the possibility that parity violating primordial gravitational waves can generate the observed matter anti-matter asymmetry and play a second crucial role in actually ending the epoch of cosmic inflation.  I discuss the potential for detecting this form of parity violating gravitational waves in future CMB missions.