On A Possible Ground State for Quantum Gravity

TL;DR

This paper presents a variational calculation suggesting that a state composed of a gas or lattice of Planck-scale wormholes could serve as the ground state of quantum gravity, potentially lower in energy than flat spacetime.

Contribution

It introduces a variational approach to estimate the ground state energy of quantum gravity around wormhole solutions, proposing a new candidate ground state involving wormhole configurations.

Findings

Wormhole-based state has lower energy than flat spacetime.

Planck-scale wormholes may form the quantum gravity ground state.

Implications for the structure of spacetime at quantum scales.

Abstract

A variational calculation is presented of the ADM-energy of the quantized gravitational field around a wormhole solution of the classical Einstein's equations. One finds the energy of such state to be in general lower than the perturbative ground state, in which the quantized gravity field fluctuates around flat (Euclidean) space-time. As a result the strong indication emerges that a gas (or a lattice) of wormholes of Planck mass and average distance $l_p$, the Planck length, may be a good approximation of the Ground State of Quantum Gravity, some implications of which are reviewed.