Large $N$ phase transition in $T \overline{T}$-deformed $2d$ Yang-Mills theory on the sphere
Leonardo Santilli, Miguel Tierz
TL;DR
This work analyzes the $T\overline{T}$-deformed $U(N)$ Yang--Mills theory on the sphere at large $N$. By recasting the deformed theory in a matrix-model framework, the authors perform a perturbative analysis in the deformation parameter $\tau$ and a nonperturbative two-cut construction for the strong-coupling phase, revealing that the Douglas--Kazakov phase transition persists for a range of $\tau$ with a lowered critical area $A_{cr}(\tau)$ and retains its third-order character. Instanton physics is shown to continue driving the transition, with the deformation enhancing instanton effects and lowering the critical area; in particular, the single-monopole sector yields a deformed exponential suppression controlled by $b_{\infty}$, consistent with a modified onset of the transition. These results illuminate how TTbar deformations modify nonperturbative phase structure in solvable gauge theories, potentially informing holographic and integrable perspectives on deformations of quantum field theories.
Abstract
We study the partition function of a $T \overline{T}$-deformed version of Yang-Mills theory on the two-sphere. We show that the Douglas-Kazakov phase transition persists for a range of values of the deformation parameter, and that the critical area is lowered. The transition is of third order and also induced by instantons, whose contributions we characterize.
