Can Quantum Gravitational Effects Influence the Entire History of the Universe?

TL;DR

This paper quantizes a flat FRW universe with dust and a cosmological constant, showing quantum effects can potentially influence the universe's entire expansion history, including inflation and late acceleration.

Contribution

It provides exact solutions to the Wheeler-DeWitt equation for a quantized universe with a cosmological constant, linking quantum effects to cosmic evolution.

Findings

Quantum effects can produce inflation and late acceleration.

Exact solutions to the Wheeler-DeWitt equation are obtained.

Quantum influence may span the entire universe history.

Abstract

In this work, a flat Friedmann-Robertson-Walker (FRW) universe with dust and a cosmological constant is quantized. By means of a canonical transformation, the classical Hamiltonian is reduced to that of either a harmonic oscillator or anti-oscillator, depending on whether $\Lambda<0$ or $\Lambda>0$, respectively. In this way exact solutions to the Wheeler-DeWitt equation can easily be obtained. It turns out that a positive cosmological constant alone may account for an early inflationary regime and a later accelerated expansion phase, with a period of decelerated expansion in between. This suggests that quantum gravitational effects can influence most of the history or even the entire history of the Universe.