Axion Longitudinal Plasma HAloscope (ALPHA) Experiment to search for the Post-Inflation Axion
POSTER
Abstract
The ALPHA (Axion Longitudinal Plasma HAloscope) experiment, which is under construction, will be placed inside the bore of a 200 mm diameter, 9 T solenoid magnet and will employ quantum-limited amplifiers to search for the post-inflation axion. Recent theoretical predictions suggest an axion mass above 40 μeV. To drive the axion search to higher frequencies (above 10 GHz), both the UC Berkeley and Stockholm groups are exploring resonator designs that utilize a metamaterial lattice of thin copper rods, whose plasma frequency can be engineered. The photonic band gap (PBG) structure in the resonator will suppress the Transverse Electric modes (TE), while confining the Transverse Magnetic modes (TM). This poster will provide an overview of the experiment and the initial prototyping and characterization of both resonator designs.
*This work has been supported by the "Table-top experiments for fundamental physics" program, sponsored by the Gordon and Betty Moore Foundation, Simons Foundation, Alfred P. Sloan Foundation, and John Templeton Foundation.
Publication: 1. Planned paper with a tentative title: A Tunable Metamaterial Resonator to Search for the Post-Inflation Axions, Shriram Jois et. al.
2. Preprint: Spiral Tuning of Wire-metamaterial Cavity for Plasma Haloscope, Jacob Lindahl et al., arXiv:2508.18145v2
3. Searching for dark matter with plasma haloscopes, Alexander J. Millar et al. Phys. Rev. D 107, 055013
Presenters
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Aarav Sindhwad
- University of California, Berkeley