Speaker
Description
Axions are a well-motivated dark matter candidate that may simultaneously solve both the strong-CP and dark matter problems. This candidate's coupling to the photon provides an especially distinct direct detection signal: in the presence of a strong magnetic field, axion-to-photon conversion induces oscillating currents within the detector at a frequency set by the axion mass. Because the viable mass parameter space spans more than ten orders of magnitude, scanning resonant experiments use high-Q resonators to enhance this signal whilst tuning across the corresponding frequency range. However, the sensitivity and scan rate of these searches are fundamentally limited by the Bode-Fano constraint, which enforces a tradeoff between bandwidth and gain for any passive, linear, time-invariant system. In this talk, we present the simulation and preliminary prototype of a "Bode-Fano evading" device that uses Josephson junctions to achieve improved gain by violating passivity and linearity assumptions. We report results from our first fabrication run and discuss the practical requirements for such a device, placing special emphasis on its implications for the sensitivity of future GUT-scale axion searches in the sub-microeV axion parameter space.