Bi-metric theory of gravity from the non-chiral Plebanski action

TL;DR

This paper presents a modified gravity theory derived from the Plebanski action, resulting in a bi-metric model with additional degrees of freedom including a massive graviton and a scalar mode.

Contribution

It introduces a novel bi-metric gravity framework from a modified Plebanski action, expanding understanding of gravity's degrees of freedom.

Findings

Identifies six extra degrees of freedom as a massive graviton and scalar mode.

Recasts the modified Plebanski action as a bi-metric theory.

Analyzes the degrees of freedom around a bi-flat background.

Abstract

We study a modification of the Plebanski action for general relativity, which leads to a modified theory of gravity with eight degrees of freedom. We show how the action can be recasted as a bi-metric theory of gravity, and expanding around a bi-flat background we identify the six extra degrees of freedom with a second, massive graviton and a scalar mode.