Topological Dimensions from Disorder and Quantum Mechanics?

TL;DR

This paper investigates the effective spatial dimensions of Anderson electrons in disordered systems, revealing a dominant dimension near 2 and suggesting a possible emergence of topological dimensions from quantum disorder effects.

Contribution

It introduces a novel method to analyze the distribution of local IR dimensions in disordered quantum systems, highlighting a potential link to topological phenomena.

Findings

Probability density peaks near dimension 2.

Dimension distribution spans approximately [4/3, 8/3].

Potential emergence of a discrete topological dimension at 2.

Abstract

We have recently shown that critical Anderson electron in $D=3$ dimensions effectively occupies a spatial region of infrared (IR) scaling dimension $d_\text{IR} \approx 8/3$. Here we inquire about the dimensional substructure involved. We partition space into regions of equal quantum occurrence probability, such that points comprising a region are of similar relevance, and calculate the IR scaling dimension $d$ of each. This allows us to infer the probability density $p(d)$ for dimension $d$ to be accessed by electron. We find that $p(d)$ has a strong peak at $d$ very close to 2. In fact, our data suggests that $p(d)$ is non-zero on the interval $[d_\text{min}, d_\text{max}] \approx [4/3,8/3]$ and may develop a discrete part ($\delta$-function) at $d=2$ in infinite-volume limit. The latter invokes the possibility that combination of quantum mechanics and pure disorder can lead to emergence of topological dimensions. Although $d_\text{IR}$ is based on effective counting of which $p(d)$ has no a priori knowledge, $d_\text{IR} \ge d_\text{max}$ is an exact feature of the ensuing formalism. Possible connection of our results to recent findings of $d_\text{IR} \approx 2$ in Dirac near-zero modes of thermal quantum chromodynamics is emphasized.