We propose methods to create fractional vortices in the cyclic state of an
F=2 spinor Bose-Einstein condensate by manipulating its internal spin structure using pulsed microwave and laser fields. The stability of such vortices is studied as a function of the rotation frequency of the confining harmonic trap both in pancake- and cigar-shaped condensates. We find a range of parameters for which the so-called
31 vortex state is energetically favorable. Such fractional vortices could be created in condensates of
87Rb atoms using current experimental techniques facilitating probing of topological defects with non-Abelian statistics.
Summary form only given. In a recent experiment, performed at the National Institute of Standards and Technology (NIST), a Mach-Zender type matter-wave interferometer was demonstrated using a sequence of laser pulses applied to a gaseous Bose-Einstein condensate. Matter-wave interferometers are essential tools for probing optically manipulated Bose-Einstein condensates (BECs) and the use of a sequence of laser pulses should enable experimenters to implement a variety of interferometer types tailored for particular applications.
Summary form only given.We have established an experimental and theoretical program focused on understanding photon atom interactions in condensates with the aim of probing the properties of condensates as well as testing our models of the interactions themselves. With a combination of laser and evaporative cooling, we are routinely creating million atom Bose-Einstein condensates of sodium atoms in the newly designed 4D magnet. Our experimental setup incorporates a candlestick atomic beam source, which provides for recirculation of uncollimated sodium atoms, The laser cooling step involves a zero-crossing Zeeman slower, magneto-optic trap, and polarization gradient cooling. The laser-cooled atom cloud is loaded into the 4D magnetic trap and adiabatically compressed to high density and an evaporative cooling process is initiated. Using a RF magnetic resonance technique, hot atoms are ejected through magnetic spin flips. After formation of the condensate in the tightly confining trap, we manipulate the condensate by adiabatically changing the trapping potential and through interaction with photons. We have developed a technique for probing the condensates directly inside the trap using near-resonant absorption imaging. This imaging technique gives high sensitivity to details of the condensate wavefunction and to its surface structure. Images of pure condensates are compared to calculations of the condensate wavefunction based on a Hartree mean field description of the two-body interaction between condensate atoms.