c = 1 Matrix models: equivalences and open-closed string duality

Abstract

We give an explicit demonstration of the equivalence between the Normal Matrix Model (NMM) of c = 1 string theory at selfdual radius and the Kontsevich-Penner (KP) model for the same string theory. We relate macroscopic loop expectation values in the NMM to condensates of the closed string tachyon, and discuss the implications for open-closed duality. As in c < 1, the Kontsevich-Miwa transform between the parameters of the two theories appears to encode open-closed string duality, though our results also exhibit some interesting differences with the c < 1 case. We also briefly comment on two different ways in which the Kontsevich model originates.