Harvard Condensed Matter Theory Seminars

Abstract

Subir Sachdev, Harvard University

Breakdown of the Landau-Ginzburg-Wilson paradigm at quantum phase transitions

I will review work on quantum transitions with multiple conventional order parameters. Berry phases carried by the defects in one order parameter causes them to acquire the symmetry properties of other, seemingly unrelated, order parameters e.g. a vortex in a superconductor is linked to the density wave order in a proximate insulator. This effect often leads to phase transitions which cannot be described within the Landau-Ginzburg-Wilson theory of classical transitions. I will discuss applications to the cuprate superconductors and cold atom systems.