Expectation value of composite field $T\bar{T}$ in two-dimensional quantum field theory

Abstract

I show that the expectation value of the composite field $T\bar{T}$, built from the components of the energy-momentum tensor, is expressed exactly through the expectation value of the energy-momentum tensor itself. The relation is derived in two-dimensional quantum field theory under broad assumptions, and does not require integrability.

12 pages