Speaker
Description
Authors:
Rustam Balafendiev, Pavel Belov, Alex Droster, Maxim Gorlach, Nolan Kowitt, Samantha Lewis, Dajie Sun, Mackenzie Wooten, Karl van Bibber
Recent theoretical work predicts the mass of the post-inflation axion to lie above 40𝜇eV (~10 GHz) [1], higher than where microwave cavity experiments can effectively reach, owing to the steeply decreasing volume of the cavity with frequency. It has recently been proposed to circumvent this limitation by replacing the microwave cavity with a wire-array metamaterial whose plasma frequency is determined by its unit cell rather than its boundary conditions, i.e. its size, as is the case with conventional microwave cavities [2]. Thus in principle it is possible to build a resonator that could be both arbitrarily high in frequency and arbitrarily large. We have performed initial investigations of the feasibility of this concept by microwave transmission measurements (𝑆21 scattering parameter), data from which we extract the plasma frequency, loss term and effective width; based on these results we can project quality factors 𝑄 > 10,000 for a resonator at cryogenic temperatures [3]. More recently we have carried out a study of the plasma frequency as a function of unit cell parameters demonstrating a dynamic range in frequency usable in an axion haloscope.
This work supported under NSF Grants No. PHY-1914199 and PHY-2209556.
1- M. Buschmann et al., Nature Communications 18, 1049 (2022).
2- M. Lawson, et al., Physical Review Letters 123, 141802 (2019).
3- M. Wooten, et al., Annalen der Physik (accepted for publication, 2023), arXiv:2203.13945v3
