“Diagrammar” and Dimensional Renormalization

Abstract

There are several possible approaches to quantum field theory. One may start with a classical system of fields, interacting through non-linear equations of motion which are subsequently “quantized”. Alternatively, one could take the physically observed particles as a starting point; then define a Hilbert space, local operator fields and an interaction Hamiltonian. More ambitious, perhaps, is the functional integral approach, which has the advantage of being obviously Lorentz covariant.

On leave from the University of Utrecht, Netherlands.