Uncovering the effective spacetime: Lessons from the effective field theory rationale

TL;DR

This paper explores a modified effective field theory approach to gravity that maintains classical phenomenology and the standard model spectrum while addressing the cosmological constant problem by altering the spacetime concept.

Contribution

It proposes a minimal modification to general relativity within an effective theory framework to circumvent the naturalness issues of the cosmological constant.

Findings

Preserves classical general relativity phenomenology

Maintains the standard model particle spectrum

Offers a new conceptual picture of spacetime

Abstract

The cosmological constant problem can be understood as the failure of the decoupling principle behind effective field theory, so that some quantities in the low-energy theory are extremely sensitive to the high-energy properties. While this reflects the genuine character of the cosmological constant, finding an adequate effective field theory framework which avoids this naturalness problem may represent a step forward to understand nature. Following this intuition, we consider a minimal modification of the structure of general relativity which as an effective theory permits to work consistently at low energies, i.e., below the quantum gravity scale. This effective description preserves the classical phenomenology of general relativity and the particle spectrum of the standard model, at the price of changing our conceptual and mathematical picture of spacetime.