What can be learnt about Instantons in the CP(N-1) Model?

In the two-dimensional CP N−1 model one can parametrize exact many-instanton solutions via N ‘constituents ’ (called ‘zindons’). This parameterization allows, in principle, a complete ‘melting ’ of individual instantons. The model is therefore well suited to study whether dynamics prefers a dilute or a completely ‘melted ’ ensemble of instantons. We study the statistical mechanics of instantons both analytically and numerically. We find that at N = 2 the instanton system collapses into zerosize instantons. At N = 3, 4 we find that well-isolated instantons are dynamically preferred though 15-25 % of instantons have a considerable overlap with others. 1