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Description
One of the major challenges facing current dark matter haloscopes is frequency tuning in a cryogenic environment. Mechanical tuning becomes increasingly impractical for plasma haloscopes operating above 20 GHz because of the extremely fine structure of the wire arrays. In this work, we propose a novel method for tuning the resonant frequency of plasma haloscopes through the kinetic inductance of superconducting nanowires. A DC current flowing through the wires modifies the Cooper-pair density and thereby shifts the plasma frequency via changes in the kinetic inductance. While this phenomenon is well known from the development of superconducting kinetic inductance detectors (KIDs), we present a new calculation of the quality factor, which is simultaneously affected by the applied current. The DC current broadens the density of states of Bogoliubov quasiparticles, leading to a nontrivial modification of the optical conductivity of the superconductor. A complete calculation of the complex conductivity enables the simultaneous determination of both the resonant frequency and the quality factor of a plasma haloscope.
| Primary Abstract Topic | Theory: Axions and Wave-Like-DM |
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