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PERIMETER INSTITUTE RECORDED SEMINAR ARCHIVE

Particle Propagators from Discrete Spacetime
Speaker(s): Steven Johnston
Abstract: How sure are you that spacetime is continuous? One of the more radical approaches to quantum gravity, causal set theory, models spacetime as a discrete structure: a causal set. Allowing the possibility that spacetime is discrete then how should we do physics on it? Carrying over the usual continuum descriptions in terms of differential equations seems like a difficult option. This talk begins with a brief introduction to causal sets then describes an approach to modelling the propagation of scalar particles on a causal set. We obtain the continuum causal retarded propagator by summing quantum mechanical amplitudes assigned to paths in the causal set - a kind of 'discrete path integral' that agrees with the continuum result. The propagator so obtained should serve as a building block towards a model for quantum field theory on a causal set.
Date: 14/04/2008 - 11:00 am
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