Collapse and revival of the monopole mode of a degenerate Bose gas in an   isotropic harmonic trap
  We study the monopole (breathing) mode of a finite temperature Bose-Einstein condensate in an isotropic harmonic trap recently developed by Lobser et al. [Nat.~Phys., \textbf{11}, 1009 (2015)]. We observe a nonexponential collapse of the amplitude of the condensate oscillation followed by a partial revival. This behavior is identified as being due to beating between two eigenmodes of the system, corresponding to in-phase and out-of-phase oscillations of the condensed and noncondensed fractions of the gas. We perform finite temperature simulations of the system dynamics using the Zaremba-Nikuni-Griffin methodology [J.~Low Temp.~Phys., \textbf{116}, 277 (1999)], and find good agreement with the data, thus confirming the two mode description. 
C. J. E. Straatsma, V. E. Colussi, M. J. Davis, D. S. Lobser, M. J.   Holland, D. Z. Anderson, H. J. Lewandowski, and E. A. ...
cond-mat.quant-gas cond-mat.stat-mech