Spacetime foam, midisuperspace, and the cosmological constant

TL;DR

This paper explores the idea that quantum fluctuations of spacetime at the Planck scale, modeled as spacetime foam, could hide a large cosmological constant, supported by evidence from a simplified midisuperspace model.

Contribution

It provides a simplified midisuperspace model demonstrating how spacetime foam can conceal a large cosmological constant and remain stable over time.

Findings

Spacetime foam can hide a large cosmological constant.

The foam structure persists under time evolution.

Simplified models support the feasibility of this mechanism.

Abstract

Perhaps the cosmological constant really is huge at the Planck scale, but is "hidden" by Planck scale quantum fluctuations of spacetime. I briefly review this proposal and provide some evidence, coming from a simplified midisuperspace model, that an appropriate "foamy" structure can do the job of hiding a large cosmological constant, and can persist under time evolution.