"Classicalquantum mappings for geometrically frustrated systems"Stephen Powell , Joint Quantum Institute [Host: Andrew James]
ABSTRACT:
Several systems have recently been demonstrated to show "nonLGW"
quantum phase transitions, with different orderings on two sides of a continuous transition. We present two examples of classical statistical systems  spin ice in a [100] magnetic field and an ordering transition of closepacked dimers on a cubic lattice  that appear to show continuous (secondorder) transitions that lie outside the Landau paradigm.
In both cases, strong local constraints mean that neither of the neighboring phases can be understood as thermally disordered, excluding the standard route to a continuum critical theory. Instead, we derive critical theories for both transitions by mapping from threedimensional classical problems to twodimensional quantum problems. For the dimer model, this mapping provides a direct connection to previous work on nonLGW transitions of lattice bosons at fractional filling factors.

Condensed Matter Seminar Thursday, October 15, 2009 4:00 PM Physics Building, Room 204 Note special time. Note special room. 
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