Proposal for Axion Dark Matter Detection Using an $LC$ Circuit

We show that dark matter axions cause an oscillating electric current to flow along magnetic field lines. The oscillating current induced in a strong magnetic field ${\overrightarrow{B}}_0$ produces a small magnetic field ${\overrightarrow{B}}_a$. We propose to amplify and detect ${\overrightarrow{B}}_a$ using a cooled $LC$ circuit and a very sensitive magnetometer. This appears to be a suitable approach to searching for axion dark matter in the $10^{-7}$ to $10^{-9}\mathrm{eV}$ mass range.

Figure 1

Schematic drawing of the proposed axion dark matter detector, in the case where the magnet is a solenoid. The two crossed rectangles indicate cross sections of the solenoid’s windings. The direction of the magnetic field (${\overrightarrow{B}}_0$) produced by the solenoid is indicated by an arrow.

Figure 2

Expected sensitivity of the proposed detector. The horizontal lines near the top indicate upper limits on $g$ from stellar evolution (horizontal branch stars) and from the Tokyo and CAST solar axion searches [20]. The shaded areas on the right are limits obtained (dark) and anticipated (lighter) by the ADMX axion dark matter search. The light shaded areas on the left show the expected sensitivity of the proposed experiment, under the assumptions spelled out in the text, using (a) the ADMX magnet and (b) the CMS magnet. The dashed line indicates how the sensitivity scales with the magnet’s physical size, keeping everything else fixed.