2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/52387I 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 pagesHigh Energy Physics - Theorytext