Fractal Theory Space: Spacetime of Noninteger Dimensionality

TL;DR

This paper develops matter field theories in fractal-like 'theory space' that exhibit noninteger dimensions, analyzing their properties, spectrum, and implications for physics beyond traditional spacetime models.

Contribution

It introduces a novel framework for constructing matter theories with fractal geometries and noninteger dimensions, extending the concept of spacetime in quantum field theory.

Findings

Models describe physics in noninteger dimensions above a RG scale M.

The spacetime dimensionality depends on lattice coordination number s.

The approach relates to thermal spin systems and involves complex RG computations.

Abstract

We construct matter field theories in ``theory space'' that are fractal, and invariant under geometrical renormalization group (RG) transformations. We treat in detail complex scalars, and discuss issues related to fermions, chirality, and Yang-Mills gauge fields. In the continuum limit these models describe physics in a noninteger spatial dimension which appears above a RG invariant ``compactification scale,'' M. The energy distribution of KK modes above M is controlled by an exponent in a scaling relation of the vacuum energy (Coleman-Weinberg potential), and corresponds to the dimensionality. For truncated-s-simplex lattices with coordination number s the spacetime dimensionality is 1+(3+2ln(s)/ln(s+2)). The computations in theory space involve subtleties, owing to the 1+3 kinetic terms, yet the resulting dimensionalites are equivalent to thermal spin systems. Physical implications are discussed.