Condensed Matter Physics Seminar
2 p.m., Thursday, March 29, 2001
Room 1201, Physics Building
Spinor Bosonic Atoms in Optical Lattices: Symmetry Breaking and
Fractionalization
Eugene Demler
(Department of Physics, Harvard University)
Abstract: A system of cold spin-1 Bose atoms with antiferromagnetic
interactions in an optical lattice is considered. It is shown that
spin dynamics in a single site is described by a rigid rotor problem with
parity constraint on possible angular momenta. Coupling between the
lattice sites is introduced via tunneling of the atoms and leads to a variety
of broken symmetry phases, including a usual polar phase, a condensate
of singlet boson pairs, and a crystal spin nematic phase. Exotic
fractionalized phases of spinor BEC are suggested and discussed in the
language of topological defect condensation and Z2 lattice
gauge theory. An interference type experiment is proposed that may
distinguish between various broken symmetry states.
Host: Sankar Das Sarma
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