Long Cycles in the Infinite-Range-Hopping Bose-Hubbard Model with Hard   Cores
  In this paper we study the relation between long cycles and Bose-Condensation in the Infinite range Bose-Hubbard Model with a hard core interaction. We calculate the density of particles on long cycles in the thermodynamic limit and find that the existence of a non-zero long cycle density coincides with the occurrence of Bose-Einstein condensation but this density is not equal to that of the Bose condensate. 
G. Boland, J.V. Pul\'e