26.05.11 17:15

Multiferroics and the Early Universe

Sinead M. Griffin (ETH Zuerich)

The idea of being able to test phenomena that occur on galactic scales and those that occur in the laboratory is simply extraordinary. The coming-together of cosmology and condensed matter theory is facilitated by the phase transitions and defect formation that is common to both areas. The key to studying both is symmetry breaking and its possible outcomes. The Kibble Mechanism describes what sort of systems can accommodate defects and the criteria for defect formation in a physical manifold. In order to fully benefit from the overlap similarities in phenomena on the very large scale and the very small scale, a quantitative measure is needed to be able to develop scaling laws and relations. This is done via the Zurek scenarios, where the density of defects is estimated from causality arguments.


Many condensed matter systems exhibit symmetry breaking and form defects analogous to those in cosmological transitions. In particular I will discuss the latest proposal for Kibble-Zurek defect formation in multiferroic YMnO3. Second harmonic generation imaging provides a unique tool for visualising and understanding the formation of topological defects in this system and in understanding the phenomenon of defect formation in spontaneously broken symmetries in general.


(Seminarraum I)

Category: Kolloquium