Physics

Dr Parijat Dey
Upsala University

Abstract :

We propose a dispersion relation in conformal field theory which expresses the four point correlator as an integral over its single discontinuity. Exploiting the analytic properties and crossing symmetry of the correlator, we show that in perturbative settings the correlator depends only on the spectrum of the theory, as well as the OPE coefficients of certain low twist operators and can be reconstructed unambiguously. As an application, the < phi phi phi phi >  correlator in phi^4 theory at the Wilson-Fisher fixed point can be computed in closed form upto order \\epsilon^2 in the \\epsilon expansion. At small coupling this can be thought of as an alternative way of computing the CFT correlators with some inputs using Feynman diagrams.