The Weinberg no-go theorem for cosmological constant and nonlocal gravity

TL;DR

This paper demonstrates that nonlocal gravity theories, such as Infinite Derivative Gravity, can bypass the Weinberg no-go theorem, offering a potential explanation for cosmic acceleration without fine-tuning or extra matter fields.

Contribution

It introduces a nonlocal gravitational framework that challenges the Weinberg no-go theorem, proposing a new approach to the cosmological constant problem.

Findings

Nonlocal gravity can evade the Weinberg no-go theorem.

Infinite Derivative Gravity may explain cosmic acceleration.

Effective field theory describes acceleration without fine-tuning.

Abstract

We show how a nonlocal gravitational interaction can circumvent the Weinberg no-go theorem on cosmological constant, which forbids the existence of any solution to the cosmological constant problem within the context of local field theories unless some fine-tuning is assumed. In particular, Infinite Derivative Gravity theories hint at a possible understanding of the cosmological constant as a nonlocal gravitational effect on very large scales. In this perspective, one can describe the observed cosmic acceleration in terms of an effective field theory without relying on the fine-tuning of parameters or additional matter fields.