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Phys. Rev. D 71, 124026 (2005) [7 pages]

Conformal geometrodynamics: True degrees of freedom in a truly canonical structure

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Charles H.-T. Wang*
School of Engineering and Physical Sciences, University of Aberdeen, King’s College, Aberdeen AB24 3UE, Scotland and Rutherford Appleton Laboratory, CCLRC, Chilton, Didcot, Oxon OX11 0QX, England

Received 20 January 2005; published 15 June 2005

The standard geometrodynamics is transformed into a theory of conformal geometrodynamics by extending the Arnowitt-Deser-Misner (ADM) phase space for canonical general relativity to that consisting of York’s mean exterior curvature time, conformal three-metric and their momenta. Accordingly, an additional constraint is introduced, called the conformal constraint. In terms of the new canonical variables, a diffeomorphism constraint is derived from the original momentum constraint. The Hamiltonian constraint then takes a new form. It turns out to be the sum of an expression that previously appeared in the literature and extra terms quadratic in the conformal constraint. The complete set of the conformal, diffeomorphism and Hamiltonian constraints are shown to be of first class through the explicit construction of their Poisson brackets. The extended algebra of constraints has as subalgebras the Dirac algebra for the deformations and Lie algebra for the conformorphism transformations of the spatial hypersurface. This is followed by a discussion of potential implications of the presented theory on the Dirac constraint quantization of general relativity. An argument is made to support the use of the York time in formulating the unitary functional evolution of quantum gravity. Finally, the prospect of future work is briefly outlined.

© 2005 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevD.71.124026
DOI:
10.1103/PhysRevD.71.124026
PACS:
04.20.Cv, 04.20.Fy, 04.60.Ds

*Electronic address: c.wang@abdn.ac.uk