Comment by bryango

Ah, to be more precise, I work in high energy theory (hep-th): https://arxiv.org/archive/hep-th. I shouldn't have spoken for theoretical physics in general, but in hep-th, mathematica is basically a requirement (nowadays, can't say for 1987). I believe the same applies to high energy phenomenology (hep-ph) in which some fundamental packages (e.g. feyncalc) are written in mathematica.