Exotic phases
and phase transitions in quantum magnetism
Michael Hermele, University of Colorado
Classifying and characterizing
states of matter and phase transitions between them is one of the most basic
tasks of condensed matter physics. In systems with only bosonic degrees of
freedom, the "standard" approach to this task is based on
construction of a Landau free energy in terms of one or more order parameters.
Exotic phases are simply those for which this approach is insufficient.
As particularly simple strongly
correlated systems, quantum magnets are a good testing ground to explore exotic
states of matter. In this tutorial talk, I will survey the current
understanding of exotic states in two- and three-dimensional quantum magnets,
and highlight some of the major open issues.