Loop quantum gravity and cosmological constant

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. (C) 2021 The Author(s). Published by Elsevier B.V.

Automated summary

This study examines a one-parameter regularization freedom of the Hamiltonian constraint for loop quantum gravity, analyzing the physical phenomena involved. It is found that for a positive value of the regularization parameter, an asymptotic de Sitter branch connected to the standard Friedmann branch can be obtained.