Topological Phases of Condensed Matter Shivaji Sondhi, Professor of Physics, Princeton University

The classic explanation for the existence of different phases of matter, due to Landau, involves ordering via broken symmetries captured in the notion of the order parameter. Recent work has explored phases that do not break symmetries but instead exhibit emergent gauge fields. I will describe some of the basic ideas that have been discussed in such work and systems, existing and hypothesized, to which they apply. These include quantum Hall states, ice, and the resonating valence bond state.