Exact TT[over ¯] Deformation of Two-Dimensional Maxwell Theory

: We study the partition function of TT[over ¯]-deformed two-dimensional Maxwell theory by solving the relevant flow equation at the level of individual flux sectors. Summing exactly the "instanton" series, we obtain a well-defined expression for the partition function at arbitrary μ. For μ>0, the spectrum of the theory experiences a truncation and the theory undergoes infinite-order quantum phase transitions associated with the vanishing of Polyakov-loop correlators. For μ<0, the appearance of nonperturbative contributions in μ drastically modifies the structure of the partition function.