Magnetic shielding and exotic spin-dependent interactions

TL;DR

This paper investigates how magnetic shielding affects the detection of exotic spin-dependent interactions, concluding that common geometries do not significantly reduce sensitivity, but induced magnetic fields in shields must be considered.

Contribution

It provides a detailed analysis of magnetic shielding effects on exotic spin interactions and suggests using flux concentrators to enhance signals.

Findings

Magnetic shields generally do not significantly reduce sensitivity to exotic interactions.

Exotic fields coupling to electron spins can induce magnetic fields inside shields.

Using flux concentrators can amplify exotic spin-dependent signals.

Abstract

Experiments searching for exotic spin-dependent interactions typically employ magnetic shielding between the source of the exotic field and the interrogated spins. We explore the question of what effect magnetic shielding has on detectable signals induced by exotic fields. Our general conclusion is that for common experimental geometries and conditions, magnetic shields should not significantly reduce sensitivity to exotic spin-dependent interactions, especially when the technique of comagnetometry is used. However, exotic fields that couple to electron spin can induce magnetic fields in the interior of shields made of a soft ferro- or ferrimagnetic material. This induced magnetic field must be taken into account in the interpretation of experiments searching for new spin-dependent interactions and raises the possibility of using a flux concentrator inside magnetic shields to amplify exotic spin-dependent signals.