Ground state of the universe and the cosmological constant. A nonperturbative analysis

TL;DR

This paper investigates the ground state of the universe in a gravity-matter system, revealing that vacuum energy density depends non-linearly on the cosmological constant and time, offering new insights into their interrelation.

Contribution

It provides a nonperturbative analysis of the universe's ground state, highlighting how vacuum energy varies with time and the cosmological constant in a volume time gauge.

Findings

Vacuum energy density is a non-linear function of the cosmological constant and time.

The analysis offers a new perspective on the relation between time, vacuum energy, and the cosmological constant.

Abstract

The physical Hamiltonian of a gravity-matter system depends on the choice of time, with the vacuum naturally identified as its ground state. We study the expanding universe with scalar field in the volume time gauge. We show that the vacuum energy density computed from the resulting Hamiltonian is a non-linear function of the cosmological constant and time. This result provides a new perspective on the relation between time, the cosmological constant, and vacuum energy.