In Search of Local Degrees of Freedom in Quadratic Diff-invariant Lagrangians

TL;DR

This paper demonstrates that four-dimensional local diff-invariant free field theories lack local degrees of freedom, challenging assumptions about the dynamical content of such theories.

Contribution

It provides a proof that local diff-invariant free theories in four dimensions do not possess local degrees of freedom, clarifying their physical nature.

Findings

Local diff-invariant free theories in 4D have no local degrees of freedom.

The result impacts the understanding of gauge invariance and dynamical content.

Supports the idea that certain gauge theories are topological in nature.

Abstract

We show that local diff-invariant free field theories in four spacetime dimensions do not have local degrees of freedom.