%0 Journal Article
%J Physical Review Letters
%D 2009
%T Number Fluctuations and Energy Dissipation in Sodium Spinor Condensates
%A Yingmei Liu
%A Eduardo Gomez
%A Stephen E. Maxwell
%A Lincoln D. Turner
%A Eite Tiesinga
%A Paul D. Lett
%X We characterize fluctuations in atom number and spin populations in F=1 sodium spinor condensates. We find that the fluctuations enable a quantitative measure of energy dissipation in the condensate. The time evolution of the population fluctuations shows a maximum. We interpret this as evidence of a dissipation-driven separatrix crossing in phase space. For a given initial state, the critical time to the separatrix crossing is found to depend exponentially on the magnetic field and linearly on condensate density. This crossing is confirmed by tracking the energy of the spinor condensate as well as by Faraday rotation spectroscopy. We also introduce a phenomenological model that describes the observed dissipation with a single coefficient.
%B Physical Review Letters
%V 102
%8 2009/6/5
%G eng
%U http://arxiv.org/abs/0906.2110v1
%N 22
%! Phys. Rev. Lett.
%R 10.1103/PhysRevLett.102.225301
%0 Journal Article
%J Physical Review Letters
%D 2009
%T Quantum Phase Transitions and Continuous Observation of Spinor Dynamics in an Antiferromagnetic Condensate
%A Yingmei Liu
%A Sebastian Jung
%A Stephen E. Maxwell
%A Lincoln D. Turner
%A Eite Tiesinga
%A Paul. D. Lett
%X Condensates of spin-1 sodium display rich spin dynamics due to the antiferromagnetic nature of the interactions in this system. We use Faraday rotation spectroscopy to make a continuous and minimally destructive measurement of the dynamics over multiple spin oscillations on a single evolving condensate. This method provides a sharp signature to locate a magnetically tuned separatrix in phase space which depends on the net magnetization. We also observe a phase transition from a two- to a three-component condensate at a low but finite temperature using a Stern-Gerlach imaging technique. This transition should be preserved as a zero-temperature quantum phase transition.
%B Physical Review Letters
%V 102
%8 2009/3/23
%G eng
%U http://arxiv.org/abs/0902.3189v1
%N 12
%! Phys. Rev. Lett.
%R 10.1103/PhysRevLett.102.125301