  We defend the Fock-space Hamiltonian truncation method, which allows to
calculate numerically the spectrum of strongly coupled quantum field theories,
by putting them in a finite volume and imposing a UV cutoff. The accuracy of
the method is improved via an analytic renormalization procedure inspired by
the usual effective field theory. As an application, we study the
two-dimensional Phi^4 theory for a wide range of couplings. The theory exhibits
a quantum phase transition between the symmetry-preserving and
symmetry-breaking phases. We extract quantitative predictions for the spectrum
and the critical coupling and make contact with previous results from the
literature. Future directions to further improve the accuracy of the method and
enlarge its scope of applications are outlined.
