TOPOLOGICAL ANTITOPOLOGICAL FUSION AND THE LARGE-N CP(N) MODEL

We discuss the large-N limit of the supersymmetric CP(N) models as an illustration of Cecotti and Vafa's tt* formalism. In this limit the ''tt* equation'' becomes the long wavelength limit of the two-dimensional Toda lattice, an equation first studied in the context of self-dual gravity. We show how simple finite-temperature and large-N techniques determine the relevant solution, and verify analytically that it solves the tt* equation, using Legendre transform techniques from self-dual gravity.