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arXiv · 1109.1012

Quantum Phase Transition in an Antiferromagnetic Spinor Bose-Einstein Condensate

E. M. Bookjans·A. Vinit·C. Raman
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Abstract

We have experimentally observed the dynamics of an antiferromagnetic sodium Bose-Einstein condensate (BEC) quenched through a quantum phase transition. Using an off-resonant microwave field coupling the F = 1 and F = 2 atomic hyperfine levels, we rapidly switched the quadratic energy shift q from positive to negative values. At q = 0 the system undergoes a transition from a polar to antiferromagnetic phase. We measured the dynamical evolution of the population in the F = 1, m_F = 0 state in the vicinity of this transition point and observed a mixed state of all 3 hyperfine components for q < 0. We also observed the coarsening dynamics of the instability for q<0, as it nucleated small domains that grew to the axial size of the cloud.

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E. M. Bookjans, A. Vinit, C. Raman. 2011-09-05. Quantum Phase Transition in an Antiferromagnetic Spinor Bose-Einstein Condensate. https://doi.org/10.1103/physrevlett.107.195306

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