I think that as you have some rough exposure to relativity already, you could first absorb the idea that Minkowski (flat) spacetime is a theory where at every p

I think that as you have some rough exposure to relativity already, you could first absorb the idea that Minkowski (flat) spacetime is a theory where at every point the Poincaré group is the isometry group. That's a good way to hit on representation theory. Representations of the Poincaré group: http://www2.ph.ed.ac.uk/~s0948358/mysite/Poincare%20Chapters%201&2.pdf http://www2.ph.ed.ac.uk/~s0948358/mysite/Poincare%20Chapters... and generalizing: https://www.wikiwand.com/en/Particle_physics_and_representation_theory https://www.wikiwand.com/en/Particle_physics_and_representat... Introductions to QFT tend to assume you know a lot of physics. An example is the Preface for Students in Srednicki's prepublication: http://web.physics.ucsb.edu/~mark/ms-qft-DRAFT.pdf http://web.physics.ucsb.edu/~mark/ms-qft-DRAFT.pdf However, Lancaster and Blundell's book has some reviews suggesting that someone good at math should be able to work through it without the background needed by textbooks like Srednicki's https://www.dur.ac.uk/physics/qftgabook/ https://www.dur.ac.uk/physics/qftgabook/ (I have not read it though).