Observables for FRW model with cosmological constant in the framework of loop cosmology

TL;DR

This paper analyzes a flat FRW cosmological model with a cosmological constant within loop quantum cosmology, deriving analytical solutions and identifying key observables, highlighting differences between standard and nonstandard approaches.

Contribution

It provides an analytical solution for a flat FRW model with a cosmological constant in loop quantum cosmology and characterizes elementary and compound observables.

Findings

Bounded and oscillating volume for negative cosmological constant

Bounded and oscillating energy density for positive cosmological constant

Unbounded but periodic volume in the model

Abstract

We consider a flat cosmological model with a free massless scalar field and the cosmological constant $\Lambda$ in the framework of loop quantum cosmology. The scalar field plays the role of an intrinsic time. We apply the reduced phase space approach. The dynamics of the model is solved analytically. We identify elementary observables and their algebra. The compound physical observables like the volume and the energy density of matter field are analysed. Both compound observables are bounded and oscillate in the $\Lambda<0$ case. The energy density is bounded and oscillates in the $\Lambda>0$ case. However, the volume is unbounded from above, but periodic. The difference between standard and nonstandard loop quantum cosmology is described.