Probabilities and signalling in quantum field theory

Dickinson, Robert and Forshaw, Jeff and Millington, Peter (2016) Probabilities and signalling in quantum field theory. Physical Review D, 93 (6). 065054/1-065054/12. ISSN 2470-0010

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Abstract

We present an approach to computing probabilities in quantum field theory for a wide class of source-detector models. The approach works directly with probabilities and not with squared matrix elements, and the resulting probabilities can be written in terms of expectation values of nested commutators and anti-commutators. We present results that help in the evaluation of these, including an expression for the vacuum expectation values of general nestings of commutators and anti-commutators in scalar field theory. This approach allows one to see clearly how faster-than-light signalling is prevented, because it leads to a diagrammatic expansion in which the retarded propagator plays a prominent role. We illustrate the formalism using the simple case of the much-studied Fermi two-atom problem.

Item Type: Article
Schools/Departments: University of Nottingham UK Campus > Faculty of Science > School of Physics and Astronomy
Identification Number: https://doi.org/10.1103/PhysRevD.93.065054
Depositing User: Millington, Peter
Date Deposited: 28 Jul 2016 11:10
Last Modified: 21 Sep 2016 07:30
URI: http://eprints.nottingham.ac.uk/id/eprint/35502

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