Local covariance and background independence

TL;DR

This paper discusses how the principle of local covariance can address the challenge of background dependence in quantum gravity, leading to background independent quantum field theories.

Contribution

It demonstrates that local covariance can be used to implement background independence, providing a conceptual framework for quantum gravity.

Findings

Locally covariant fields are background independent entities.

Local covariance restricts renormalization freedom in quantum field theories.

The approach offers a way to reconcile quantum field theory with background independence.

Abstract

One of the many conceptual difficulties in the development of quantum gravity is the role of a background geometry for the structure of quantum field theory. To some extent the problem can be solved by the principle of local covariance. The principle of local covariance was originally imposed in order to restrict the renormalization freedom for quantum field theories on generic spacetimes. It turned out that it can also be used to implement the request of background independence. Locally covariant fields then arise as background independent entities.