Author(s): Jie Gu, Jue Hou, and Yunfeng Jiang We apply harmonic analysis to study the $T\overline{T}$-deformed torus partition function. We first express the CFT partition functions in terms of Maass waveforms, including the Eisenstein series and cusp forms. These basis functions turn out to deform in a very simple way under the $T\overline{T}$… [Phys. Rev. Lett. 137, 081603] Published Fri Aug 21, 2026