Events at Physics
Events on Tuesday, October 20th, 2015
- Chaos & Complex Systems Seminar
- What climate change and world change really mean for all of us
- Time: 12:05 pm
- Place: 4274 Chamberlin (refreshments will be served)
- Speaker: Bernard Z. Friedlander, Department of Psychology, Emeritus, University of Hartford
- Abstract: Can American and World politicians face the possibilities that some of our smartest scientists may be right about Climate Change? That’s what this presentation seeks to understand and explain: the standoff between– Authoritative assessments from massive bodies of data that forecast high probabilities of many widespread catastrophes; and Persistent struggles among some of our most powerful political and economic leaders to preserve business as usual. CCSS concepts of simplicity, intricacy, complexity and chaos appear to account for problems that must be overcome if America and the World can solve these problems before it’s too late.
- Host: Sprott
- Theory Seminar (High Energy/Cosmology)
- Galilean creation of the inflationary universe
- Time: 3:30 pm
- Place: 5280 Chamberlin Hall
- Speaker: Masahide Yamaguchi, Tokyo Institute of Technology
- Abstract: It has been pointed out that the null energy condition can be violated stably in some non-canonical scalar-field theories. This allows us to consider the Galilean Genesis scenario in which the universe starts expanding from Minkowski spacetime and hence is free from the initial singularity. We use this scenario to study the early-time completion of inflation, pushing forward the recent idea of Pirtskhalava et al. We present a generic form of the Lagrangian governing the background and perturbation dynamics in the Genesis phase, the subsequent inflationary phase, and the graceful exit from inflation, as opposed to employing the effective field theory approach. Our Lagrangian belongs to a more general class of scalar-tensor theories than the Horndeski theory and Gleyzes-Langlois-Piazza-Vernizzi generalization, but still has the same number of the propagating degrees of freedom, and thus can avoid Ostrogradski instabilities. We investigate the generation and evolution of primordial perturbations in this scenario and show that one can indeed construct a stable model of inflation preceded by (generalized) Galilean Genesis.
- Host: Amol Upadhye