We present a novel approach to computing transition probabilities in quantum field theory, which allows them to be written directly in terms of expectation values of nested commutators and anti-commutators of field operators, rather than squared matrix elements. We show that this leads to a diagrammatic expansion in which the retarded propagator plays a dominant role. As a result, one is able to see clearly how faster-than-light signalling is prevented between sources and detectors. Finally, we comment on potential implications of this approach for dealing with infra-red divergences.
|Journal||Journal of Physics: Conference Series|
|Early online date||18 Aug 2017|
|Publication status||Published - 2018|
|Event||8th International Workshop on Decoherence, Information, Complexity and Entropy, DICE 2016 - Castiglioncello, Italy|
Duration: 12 Sep 2016 → 16 Sep 2016