Nonperturbative aspects of two-dimensional $T\bar{T}$-deformed scalar theory from functional renormalization group

We study $T\bar{T}$-deformed $O(N)$ scalar field theory in two-dimensional spacetime using the functional renormalization group. We derive the $\beta$ functions for the couplings in the system and explore the fixed points. In addition to the Gaussian (trivial) fixed point, we find a nontrivial fixed point at which a new universality class exists. The deformation parameter becomes relevant at the nontrivial fixed point. Therefore, the $T\bar T$-deformed scalar field theory in two-dimensional spacetime could be defined as a nonperturbatively renormalizable theory.