# This Week at Physics

## Events at Physics |
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### Events on Friday, October 19th, 2018

**Theory Seminar (High Energy/Cosmology)****Consistency relations in multi-field inflation****Time:**2:00 pm**Place:**5310 Chamberlin Hall**Speaker:**Jinn-Ouk Gong, KASI**Abstract:**The consequences of spatial coordinate transformation in multi-field inflation are studied. Among the spontaneously broken de Sitter isometries, only dilatation in the comoving gauge preserves the form of the metric and thus results in quantum-protected Slavnov-Taylor identities. The corresponding consistency relations between correlation functions of cosmological perturbations are derived in two different ways, by the connected and one-particle-irreducible Green's functions. The lowest-order consistency relations are explicitly given, and even in multi-field inflation the consistency relations in the soft limit are independent of the detail of the matter sector.**Physics Department Colloquium****The Physics of Divergence: Resurgence and Non-Perturbative Physics****Time:**3:30 pm**Place:**2241 Chamberlin Hall**Speaker:**Gerald Dunne, University of Connecticut**Abstract:**Solvable interesting problems in physics are very rare. Almost all nontrivial problems require approximations, the most common of which is perturbation theory. We are all familiar with the basic idea of perturbation theory, but it holds some surprising secrets, which can be understood physically. These secrets also introduce some novel concepts from a new mathematical formalism called "resurgent asymptotics". The talk is largely non-technical, concentrating on the key physical ideas and examples, illustrated with applications in quantum mechanics and quantum field theory.**Host:**Alex Levchenko