Multiple phases and meromorphic deformations of unitary matrix models

We study a unitary matrix model with Gross-Witten-Wadia weight function and determinant insertions. After some exact evaluations, we characterize the intricate phase diagram. There are five possible phases: an ungapped phase, two different one-cut gapped phases other two-cut phases. The transition from to any is third order, but between second order. physics of tunneling metastable vacuum stable one releases instantons discussed. Wilson loops, $\beta$-functions aspects chiral symmetry breaking investigated as well. Furthermore, in detail meromorphic deformation general class models, which integration contour not anchored unit circle. ensuing diagram characterized by symplectic singularities captured Hasse