Topological susceptibility and string tension in CP(N-1) models
  We investigate the features of ${\rm CP}^{N-1}$ models concerning confinement and topology. In order to study the approach to the large-$N$ asymptotic regime, we determine the topological susceptibility and the string tension for a wide range of values of $N$, in particular $N=4,10,21,41$. Quantitative agreement with the large-$N$ predictions is found for the ${\rm CP}^{20}$ and the ${\rm CP}^{40}$ models. Problems related to the measure of the topological susceptibility and the string tension on the lattice are discussed. 
Massimo Campostrini, Paolo Rossi, and Ettore Vicari (Dipartimento di   Fisica dell'Universit\`a and Istituto Nazionale di Fi...