Cleaning up the cosmological constant

TL;DR

This paper proposes a new method to neutralize the vacuum energy's effect on the cosmological constant by coupling matter to a specially constructed metric, allowing empirical determination of vacuum curvature without zero-point energy concerns.

Contribution

It introduces a novel coupling scheme involving a composite metric linked to a topological invariant, which screens vacuum energy contributions and avoids Ostrogradski ghosts, consistent with physical tests.

Findings

The proposed theory effectively screens vacuum energy contributions.

The model is free from Ostrogradski ghosts.

It aligns with solar system and cosmological observations.

Abstract

We present a novel idea for screening the vacuum energy contribution to the overall value of the cosmological constant, thereby enabling us to choose the bare value of the vacuum curvature empirically, without any need to worry about the zero-point energy contributions of each particle. The trick is to couple matter to a metric that is really a composite of other fields, with the property that the square-root of its determinant is the integrand of a topological invariant, and/or a total derivative. This ensures that the vacuum energy contribution to the Lagrangian is non-dynamical. We then give an explicit example of a theory with this property that is free from Ostrogradski ghosts, and is consistent with solar system physics and cosmological tests.