Does a cosmological constant with a measurement constraint enable the existence of spacetime?

Abstract

We ask a basic question about how or if the existence of observable spacetime (not only its geometry) is predicted in solutions to the Einstein equations of general relativity (GR). Here the simplest case of the GR action containing the cosmological constant term and a constraint that generates the observable measurement condition are considered. We find that including the latter suggests that a cosmological constant serves as a sufficient requirement for enabling the existence of an observable spacetime.