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SUMMARY:Topological phases in 1D: An entanglement point of view - Frank Po
 llmann\, Max Planck Institute for the Physics of Complex Systems\, Dresden
DTSTART:20110602T131500Z
DTEND:20110602T141500Z
UID:TALK31089@talks.cam.ac.uk
CONTACT:Dr G Moller
DESCRIPTION:We propose a scheme to classify gapped phases of one dimension
 al systems in terms of properties of the entanglement spectrum. We discuss
  the application of this scheme to the classification of phases in two spe
 cific examples. The first example is the Haldane phase of S=1 chains. We s
 how that the Haldane phase is protected by certain symmetries and characte
 rized by a double degeneracy of the entanglement spectrum. The degeneracy 
 cannot be lifted unless either a phase boundary to another\, "topologicall
 y trivial"\, phase is crossed or the symmetry is broken. In the second exa
 mple we apply these concepts to classify systems of interacting fermions i
 n one dimension in the presence of time reversal and parity symmetry.
LOCATION:TCM Seminar Room\, Cavendish Laboratory
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