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The general scalar–tensor Hamiltonian with deformed covariance

Research output: Contribution to journalArticle

Original languageEnglish
Article number125010
Pages (from-to)125010
JournalClassical and Quantum Gravity
Issue number12
Publication statusPublished - 29 Jun 2019

King's Authors


We derive the scalar–tensor Hamiltonian constraint to all orders of momenta when the canonical constraint algebra is deformed by a phase space function as predicted by some studies into loop quantum cosmology. We find that the momenta and spatial derivatives from gravity and matter fields must combine in a very specific form to maintain a deformed general covariance. This suggests that the deformation should be equally caused by matter field derivatives as it is by gravitational curvature. We demonstrate the cosmological consequences of a variety of deformation functions. Some cause a big bounce at high energy densities and others cause a sudden singularity.

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