2016
= 2016
{scope}
{title2=A15088W1}
Source paper: https://www.whatdotheyknow.com/request/oxford_physics_past_papers_2/response/2340696/attach/4/Physics%20Papers%202015.pdf?cookie_passthrough=1
Solutions use <natural units> $\hbar=c=1$ and <Minkowski metric> $\eta=\operatorname{diag}(1,-1,-1,-1)$. The <d'Alembert operator> is $\Box=\partial_\mu\partial^\mu$. All four questions are covered, including the optional fourth question.