Loop quantum gravity and cosmological constant

TL;DR

This paper explores how a one-parameter regularization in loop quantum gravity can produce a cosmological constant consistent with observations, connecting quantum bounce phenomena with an emergent de-Sitter universe.

Contribution

It introduces a generalized model of loop quantum cosmology with a regularization parameter that can produce an effective cosmological constant matching observations.

Findings

Quantum bounce persists in the generalized model.

An asymptotic de-Sitter universe emerges for positive regularization parameter.

The effective Newtonian constant aligns with experimental constraints.

Abstract

An 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.