Dirac fields in loop quantum gravity and big bang nucleosynthesis

Martin Bojowald, Rupam Das, and Robert J. Scherrer
Phys. Rev. D 77, 084003 – Published 7 April 2008

Abstract

Big bang nucleosynthesis requires a fine balance between equations of state for photons and relativistic fermions. Several corrections to equation of state parameters arise from classical and quantum physics, which are derived here from a canonical perspective. In particular, loop quantum gravity allows one to compute quantum gravity corrections for Maxwell and Dirac fields. Although the classical actions are very different, quantum corrections to the equation of state are remarkably similar. To lowest order, these corrections take the form of an overall expansion-dependent multiplicative factor in the total density. We use these results, along with the predictions of big bang nucleosynthesis, to place bounds on these corrections and especially the patch size of discrete quantum gravity states.

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  • Received 31 October 2007

DOI:https://doi.org/10.1103/PhysRevD.77.084003

©2008 American Physical Society

Authors & Affiliations

Martin Bojowald

  • Institute for Gravitation and the Cosmos, The Pennsylvania State University, 104 Davey Lab, University Park, Pennsylvania 16802, USA

Rupam Das

  • Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235 and Institute for Gravitation and the Cosmos, The Pennsylvania State University, 104 Davey Lab, University Park, Pennsylvania 16802, USA

Robert J. Scherrer

  • Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235, USA

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Vol. 77, Iss. 8 — 15 April 2008

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