“RG Flow from phi^4 Theory to the 2D Ising Model”
We study 1+1 dimensional phi^4 theory using the recently proposed method of conformal truncation. In this method, CFT data is used to perform controlled, numerical computations in strongly-coupled QFTs, in any spacetime dimension. We compute non-perturbative spectral densities of several local operators, which are equivalent to real-time, infinite-volume correlation functions. These spectral densities, which include the Zamolodchikov C-function along the full RG flow, are calculable at any value of the coupling. Near criticality, our numerical results reproduce correlation functions in the 2D Ising model.