Aspects of Information Theory in Curved Space

Abstract

The often-asked question whether space-time is discrete or continuous may not be the right question to ask: Mathematically, it is possible that space-time possesses the differentiability properties of manifolds as well as the ultraviolet finiteness properties of lattices. Namely, physical fields in space-time could possess a finite density of degrees of freedom in the following sense: if a field's amplitudes are given on a sufficiently dense set of discrete points then the field's amplitudes at all other points of the manifold are fully determined and calculable. Which lattice of sampling points is chosen should not matter, as long as the lattices' spacings are tight enough, for example, not exceeding the Planck distance. This type of mathematical structure is known within information theory, as sampling theory, and it plays a central role in all of digital signal processing.