Unearthing wave-function renormalization effects in the time evolution   of a Bose-Einstein condensate
  We study the time evolution of a Bose-Einstein condensate in an accelerated optical lattice. When the condensate has a narrow quasimomentum distribution and the optical lattice is shallow, the survival probability in the ground band exhibits a steplike structure. In this regime we establish a connection between the wave-function renormalization parameter $Z$ and the phenomenon of resonantly enhanced tunneling. 
Paolo Facchi, Saverio Pascazio, Francesco V. Pepe, Ennio Arimondo,   Donatella Ciampini and Oliver Morsch
quant-ph cond-mat.quant-gas