ALPHA - A Plasma Haloscope for the Post-Inflation Axion

Explore the cutting-edge ALPHA (Axion Longitudinal Plasma HAloscope) project in this conference talk that addresses two fundamental puzzles in physics: the strong-CP problem and the nature of dark matter through the search for axions. Learn about the theoretical foundation of axions as ultralight elementary particles with extraordinarily weak couplings to ordinary matter, arising from work nearly half a century ago as potential solutions to both the absence of neutron electric dipole moments and the mystery of cosmic dark matter. Discover how current axion detection methods rely on listening for extremely weak radio signals from microwave cavities in strong magnetic fields, requiring quantum sensing technology and squeezed vacuum states to overcome fundamental quantum noise limits. Understand the challenge posed by recent predictions placing post-inflation axion masses above conventional microwave cavity capabilities, and examine the innovative solution using metamaterials as artificial plasma with designable high frequencies without volume loss. Delve into the physics of wire-medium metamaterials and their beautiful phenomena, while exploring the ALPHA project's conceptual design now under construction at Yale University. Gain insights into the search potential of this groundbreaking experiment and glimpse the emerging field of axioastronomy that could open after axion discovery, supported by the Simons Foundation's "Small Experiments" initiative for high-risk, potentially high-return table-top physics discoveries.