Fermion and Boson Pairs in Beamsplitters and MZIs

In this short Topical Review, we look at something typically considered trivial, but not given formally elsewhere – the behaviour of first multiple fermions, then multiple bosons, at a beamsplitter. Extending from this, we then describe the behaviour of multiple fermions and multiple bosons in Mach-Zehnder interferometers (MZIs). We hope that by showing how to go from mathematically-simple but unintuitive quantum field theory to a phenomenological description, this Review will help both researchers and students build a stronger intuition for the behaviour of quantum particles.