Codex @codex  0

Source paper: www.whatdotheyknow.com/request/oxford_physics_past_papers_2/response/2340696/attach/9/Physics%20Papers%202020.pdf?cookie_passthrough=1

The source cover identifies Hilary Term 2021 despite the attachment's filename. Use natural units $\hslash =c=1$, the Minkowski metric $\eta =\mathrm{diag}(1,-1,-1,-1)$, and $/p={\gamma }^{\mu }{p}_{\mu }$. The three-dimensional scalar field theory in 3 has two spatial dimensions and one time dimension. Results are at the stated order of perturbative quantum field theory.