Searching for Extra Dimensions and New String-Inspired Forces in the Casimir Regime

TL;DR

This paper reviews the motivation and challenges of testing gravity at sub-millimeter scales, focusing on the influence of Casimir forces and proposing experimental designs to detect potential new forces or extra dimensions.

Contribution

It introduces schematic designs for null experiments using iso-electronic and finite-size effects to overcome challenges posed by Casimir forces in short-distance gravity tests.

Findings

Identifies obstacles in measuring gravity below 10^-4 m due to Casimir forces

Proposes experimental schemes to mitigate Casimir effects in future tests

Highlights potential for discovering new forces or extra dimensions

Abstract

The appearance of new fundamental forces and extra-dimensional modifications to gravity in extensions of the Standard Model has motivated considerable interest in testing Newtonian gravity at short distances (<10^-3 m). Presently a number of new gravity experiments are searching for non-Newtonian effects in the ranges 10^-4 m -- 10^-3 m. However, as challenging as these experiments are, formidable new obstacles await the next generation of experiments which will probe gravity at distances <10^-4 m where Casimir/van der Waals forces become dominant. Here we will review the motivation for conducting such very short distance gravity experiments, and discuss some of the new problems that may arise in future experiments. Finally, we suggest schematic designs for null experiments which would address some of these problems using the ``iso-electronic'' and ``finite-size'' effects.