Integrable sigma models and universal root \(T\overline{T }\) deformation via Courant-Hilbert approach
摘要
We develop a unified Courant-Hilbert framework for constructing two-dimensional integrable sigma models deformed by two couplings: a marginal one γ and an irrelevant one λ. The integrability condition is encoded in a nonlinear partial differential equation (PDE) for two invariants (P1, P2), whose general solution could be expressed through an arbitrary generating function ℓ(τ). This formulation encompasses and extends known models, such as ModMax and Born-Infeld, while introducing new classes of solvable models with closed-form Lagrangians, including those with logarithmic and q-deformations. All resulting theories obey a universal root-