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SUMMARY:Probabilities and signalling in quantum field theory
DTSTART;VALUE=DATE-TIME:20160914T090000Z
DTEND;VALUE=DATE-TIME:20160914T103000Z
DTSTAMP;VALUE=DATE-TIME:20191113T144001Z
UID:indico-event-11920@agenda.infn.it
DESCRIPTION:\n \nWe present an approach to computing probabilities in q
uantum field theory for a wide class of source-detector models. The approa
ch works directly with probabilities and not with squared matrix elements\
, and the resulting probabilities can be written in terms of expectation v
alues of nested commutators and anticommutators. We present results that h
elp in the evaluation of these\, including an expression for the vacuum ex
pectation values of general nestings of commutators and anticommutators in
scalar field theory. This approach allows one to see clearly how faster-t
han-light signalling is prevented\, because it leads to a diagrammatic exp
ansion in which the retarded propagator plays a prominent role. We illustr
ate the formalism using the simple case of the much-studied Fermi two-atom
problem.\n\n\n\nhttps://agenda.infn.it/event/11920/
LOCATION:LNF Aula Seminari
URL:https://agenda.infn.it/event/11920/
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