Title:	A criterion for covariance in complex sequential growth models
Authors:	Surya, Sumati Zalel, Stav
Keywords:	quantum gravity discrete spacetime measure theory covariant observables
Issue Date:	Oct-2020
Publisher:	IOP Publishing Ltd.
Citation:	Classical and Quantum Gravity, 2020, Vol.37, p195030
Abstract:	The classical sequential growth model for causal sets provides a template for the dynamics in the deep quantum regime. This growth dynamics is intrinsically temporal and causal, with each new element being added to the existing causal set without disturbing its past. In the quantum version, the probability measure on the event algebra is replaced by a quantum measure, which is Hilbert space valued. Because of the temporality of the growth process, in this approach, covariant events (or observables) are measurable only if the quantum measure extends to the associated sigma algebra of events. This is not always guaranteed. In this work we find a criterion for extension (and thence covariance) in complex sequential growth models for causal sets. We find a large family of models in which the measure extends, so that all covariant events/observables are measurable.
Description:	Restricted Access.
URI:	http://hdl.handle.net/2289/7544
ISSN:	0264-9381 1361-6382 (Online)
Alternative Location:	https://ui.adsabs.harvard.edu/abs/2020CQGra..37s5030S/abstract https://arxiv.org/abs/2003.11311 https://doi.org/10.1088/1361-6382/ab987f
Copyright:	2020 IOP Publishing Ltd.
Appears in Collections:	Research Papers (TP)

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