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Signature change events: a challenge for quantum gravity?

Lookup NU author(s): Dr Angela White


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Within the framework of either Euclidean ( functional integral) quantum gravity or canonical general relativity the signature of the manifold is a priori unconstrained. Furthermore, recent developments in the emergent spacetime programme have led to a physically feasible implementation of ( analogue) signature change events. This suggests that it is time to revisit the sometimes controversial topic of signature change in general relativity. Specifically, we shall focus on the behaviour of a quantum field defined on amanifold containing regions of different signature. We emphasize that regardless of the underlying classical theory, there are severe problems associated with any quantum field theory residing on a signature-changing background. ( Such as the production of what is naively an infinite number of particles, with an infinite energy density.) We show how the problem of quantum fields exposed to finite regions of Euclidean-signature (Riemannian) geometry has similarities with the quantum barrier penetration problem. Finally we raise the question as to whether signature change transitions could be fully understood and dynamically generated within ( modified) classical general relativity, or whether they require the knowledge of a theory of quantum gravity.

Publication metadata

Author(s): White A, Weinfurtner S, Visser M

Publication type: Article

Publication status: Published

Journal: Classical and Quantum Gravity

Year: 2010

Volume: 27

Issue: 4

Print publication date: 25/01/2010

ISSN (print): 0264-9381

ISSN (electronic): 1361-6382

Publisher: Institute of Physics Publishing Ltd.


DOI: 10.1088/0264-9381/27/4/045007


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