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Loop quantum gravity and cosmological constant. (English) Zbl 1483.83025

Summary: A one-parameter regularization freedom of the Hamiltonian constraint for loop quantum gravity is analyzed. The corresponding spatially flat, homogenous and isotropic model includes the two well-known models of loop quantum cosmology as special cases. The quantum bounce nature is tenable in the generalized cases. For positive value of the regularization parameter, the effective Hamiltonian leads to an asymptotic de-Sitter branch of the Universe connecting to the standard Friedmann branch by the quantum bounce. Remarkably, by suitably choosing the value of the regularization parameter, the observational cosmological constant can emerge at large volume limit from the effect of quantum gravity, and the effective Newtonian constant satisfies the experimental restrictions in the meantime.

MSC:

83C45 Quantization of the gravitational field
83F05 Relativistic cosmology
70H45 Constrained dynamics, Dirac’s theory of constraints
14B25 Local structure of morphisms in algebraic geometry: étale, flat, etc.
83C15 Exact solutions to problems in general relativity and gravitational theory

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