Infinite Family of Integrable Sigma Models Using Auxiliary Fields.

We introduce a class of 2D sigma models which are parametrized by a function of one variable. In addition to the physical field g, these models include an auxiliary field v_{α} which mediates interactions in a prescribed way. We prove that every theory in this family is classically integrable, in that it possesses an infinite set of conserved charges in involution, which can be constructed from a Lax representation for the equations of motion.

Root-TT[over ¯] Deformations in Two-Dimensional Quantum Field Theories.

In this Letter, we introduce a one-parameter deformation of two-dimensional quantum field theories generated by a nonanalytic operator that we call Root-TT[over ¯]. For a conformal field theory, the operator coincides with the square root of the TT[over ¯] operator. More generally, the operator is defined so that classically it is marginal and generates a flow that commutes with the TT[over ¯] flow.