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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