Comments on Background Independence and Gauge Redundancies

Understand

We describe the definition and the role background independence and the closely related notion of diffeomorphism invariance play in modern string theory.

• These important concepts are transformed by a new understanding of gauge redundancies and their implementation in non-perturbative quantum field theory and quantum gravity.
• This new understanding also suggests a new role for the so-called background-independent approaches to directly quantize the gravitational field.
• This article is intended for a general audience, and is based on a plenary talk given in the Loops 2007 conference in Morelia, Mexico.