Search for exotic short-range interactions using paramagnetic insulators

TL;DR

This paper proposes an experimental approach using paramagnetic insulators to search for exotic spin-dependent short-range forces, potentially surpassing current limits by over ten orders of magnitude.

Contribution

It introduces a novel experimental setup leveraging solid-state paramagnetic insulators and cryogenic magnetometry to detect exotic interactions with unprecedented sensitivity.

Findings

Potential sensitivity over ten orders of magnitude greater than current limits.

Use of existing experimental techniques with added modifications for new force detection.

Feasibility of exploring monopole-dipole forces on polarized electrons.

Abstract

We describe a proposed experimental search for exotic spin-coupled interactions using a solid-state paramagnetic insulator. The experiment is sensitive to the net magnetization induced by the exotic interaction between the unpaired insulator electrons with a dense, non-magnetic mass in close proximity. An existing experiment has been used to set limits on the electric dipole moment of the electron by probing the magnetization induced in a cryogenic gadolinium gallium garnet sample on application of a strong electric field. With suitable additions, including a movable source mass, this experiment can be used to explore "monopole-dipole" forces on polarized electrons with unique or unprecedented sensitivity. The solid-state, non-magnetic construction, combined with the low-noise conditions and extremely sensitive magnetometry available at cryogenic temperatures could lead to a sensitivity over ten orders of magnitude greater than exiting limits in the range below 1 mm.