TY - JOUR T1 - Spinor dynamics in an antiferromagnetic spin-1 thermal Bose gas JF - Physical Review Letters Y1 - 2013 A1 - Hyewon K. Pechkis A1 - Jonathan P. Wrubel A1 - Arne Schwettmann A1 - Paul F. Griffin A1 - Ryan Barnett A1 - Eite Tiesinga A1 - Paul D. Lett AB - We present experimental observations of coherent spin-population oscillations in a cold thermal, Bose gas of spin-1 sodium-23 atoms. The population oscillations in a multi-spatial-mode thermal gas have the same behavior as those observed in a single-spatial-mode antiferromagnetic spinor Bose Einstein condensate. We demonstrate this by showing that the two situations are described by the same dynamical equations, with a factor of two change in the spin-dependent interaction coefficient, which results from the change to particles with distinguishable momentum states in the thermal gas. We compare this theory to the measured spin population evolution after times up to a few hundreds of ms, finding quantitative agreement with the amplitude and period. We also measure the damping time of the oscillations as a function of magnetic field. VL - 111 UR - http://arxiv.org/abs/1306.4255v1 CP - 2 J1 - Phys. Rev. Lett. U5 - 10.1103/PhysRevLett.111.025301 ER -