570 research outputs found
Classifying vortices in S= 3 Bose-Einstein condensates
Motivated by the recent realization of a Cr Bose-Einstein condensate,
we consider the phase diagram of a general spin-three condensate as a function
of its scattering lengths. We classify each phase according to its ``reciprocal
spinor,'' using a method developed in a previous work. We show that such a
classification can be naturally extended to describe the vortices for a spinor
condensate by using the topological theory of defects. To illustrate, we
systematically describe the types of vortex excitations for each phase of the
spin-three condensate
Dynamical Crystallization in the Dipole Blockade of Ultracold Atoms
We describe a method for controlling many-body states in extended ensembles
of Rydberg atoms, forming crystalline structures during laser excitation of a
frozen atomic gas. Specifically, we predict the existence of an excitation
number staircase in laser excitation of atomic ensembles into Rydberg states.
Each step corresponds to a crystalline state with a well-defined of regularly
spaced Rydberg atoms. We show that such states can be selectively excited by
chirped laser pulses. Finally, we demonstarte that, sing quantum state transfer
from atoms to light, such crystals can be used to create crystalline photonic
states and can be probed via photon correlation measurements
Microscopic Electron Models with Exact SO(5) Symmetry
We construct a class of microscopic electron models with exact SO(5) symmetry
between antiferromagnetic and d-wave superconducting ground states. There is an
exact one-to-one correspondence between both single-particle and collective
excitations in both phases. SO(5) symmetry breaking terms can be introduced and
classified according to irreducible representations of the exact SO(5) algebra.
The resulting phase diagram and collective modes are identical to that of the
SO(5) nonlinear sigma model.Comment: 5 pages, LATEX, 4 eps fig
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