Nucleation and growth of vortical Wigner molecules in a rotating BEC.

An analytic expression for the ground-state wavefunction of a rotating Gross-Pitaevskii condensate of trapped atoms describes the onset of vorticity in an accelerated trap, starting from the vortex entry followed by formation of growing symmetric Wigner molecules [1]. Within a unified picture, it explains the staircase of the angular momentum jumps and the behavior of the bosonic occupancies observed in numerical and variational studies \hbox{[2-4]}. The similarity of this behavior and mesoscopic superconductors is discussed. \par\noindent [1] O.K. Vorov, P. Van Isacker, M.S. Hussein and K. Bartschat, submitted to Phys. Rev. Lett. (2005). \par\noindent [2] D.A. Butts and D.S. Rokhsar, Nature {\bf 397}, 327 (1999). \par\noindent [3] G.M. Kavoulakis, B. Mottelson, and C.J. Pethick, Phys. Rev. A {\bf 62}, 063605 (2000). \par\noindent [4] X.J. Liu, H. Hu, L. Chang, W. Zhang, S.Q. Li, and Y.Z. Wang, Phys. Rev. Lett. {\bf 87}, 030404 (2001).