Zero interface tension at the deconfining phase transition for a matrix model of a $SU(\mathrm{\infty })$ gauge theory

Using a matrix model, we model the deconfining phase transition at nonzero temperature for a SU(N) gauge theory at large $N$. At infinite $N$ the matrix model exhibits a Gross-Witten-Wadia transition. We show that as a consequence, both the order-disorder and the order-order interface tensions vanish identically at the critical temperature $T_d$. We estimate how these quantities vanish in the matrix model as $T\to T_d$ and as $N \rightarrow \infty$. The numerical solution of the matrix model suggests possible non-monotonic behavior in $N$ for relatively small values of $N\sim 5$.