University of Waterloo
200 University Avenue West
Waterloo, Ontario, Canada N2L 3G1
Phone: (519) 888-4567 ext 32215
Fax: (519) 746-8115
Perimeter Institute for Theoretical Physics
Dr. East is working at the interface of gravitational physics, astrophysics, and cosmology. His research is primarily focused on understanding strong field gravity, using the tools of numerical relativity.
All are welcome to attend.
In this talk I will discuss several questions about our early cosmic history, leading up to, and during a period of exponential expansion, where the strong field dynamics of spacetime and black holes may have played a role a significant role. To begin with, such an inflationary period is usually invoked to explain the large scale homogeneity and isotropy of the Universe. However, there have remained important questions about the conditions from which inflation can actually start when homogeneity is not assumed to begin with it. I will describe the circumstances under which inflation can eventually arise from very inhomogeneous initial conditions where the gradient and kinetic energy of the putative inflaton dominates over the potential energy, including the case where the gravitational pull of over-densities is strong enough to form black holes.
I will also discuss the possible role of an instability in the Higgs boson during inflation. If the Standard Model of particle physics is extrapolated to very high energy scales, it indicates that the Higgs field should become unstable at large values. Though our electroweak vacuum is metastable on timescales that are long compared to the age of the Universe, during a period of inflation, the Higgs field would have experienced large fluctuations which could have driven it towards its true vacuum at negative energy in some regions. I will demonstrate the dynamics and growth of unstable Higgs fluctuations in an expanding spacetime, and illustrate how they can halt inflation in the regions they develop, leading to crunching regions and the development of black holes. I will also describe how a future measurement of the energy scale of inflation from the Cosmic Microwave Background could therefore reveal something about the Higgs boson and beyond Standard Model physics.