Enhancing the Scan Rate of a Dark Matter Axion Search: Quantum Noise Evasion and Maximally Informative Analysis

  • July 15, 2019, 2:00 pm
  • Daniel Palken, JILA / University of Colorado, Boulder
  • Gordon Krnjaic


Putative axion particles are well motivated solutions to the outstanding mystery of the universe’s dark matter, yet their extremely feeble coupling to ordinary matter makes them difficult to detect. The axion haloscope, first realized experimentally three decades ago, remains among the most viable detection platforms, but even today’s leading technology would take many of millennia to search out meaningful fractions axion parameter space. Today’s axion direct detection community is searching therefore not just for the elusive particles, but for technologies and innovations that will enable present and future generations of detectors to perform their searches more rapidly.

In this talk, I will present two such innovations and their use in the Haloscope At Yale Sensitive to Axion Cold dark matter (HAYSTAC) experiment. First, the resource of quantum squeezing sequesters the noise of a haloscope measurement into unmeasured observables, improving the sensitivity bandwidth and hence the search rate of the detector. Second, valuable information pertinent to the existence of the axion is discarded by the standard hypothesis testing framework used to look for axions. An alternative, Bayesian analysis utilizes the full information content of the haloscope measurement, yielding a tangible speedup at zero operational or hardware cost. These innovations will compound to accelerate HAYSTAC’s upcoming axion search threefold.