Superconducting quantum sensors for sub-micro eV axion searches

Hsiao-Mei Cho^1*

¹SLAC National Accelerator Laboratory, Menlo Park, USA

* Presenter:Hsiao-Mei Cho, email:hmscho@slac.stanford.edu

Superconducting quantum sensors have been shown to enhance the science reach of searches for ultralight (sub-meV), wavelike dark matter candidates including QCD axions which solves the Strong CP problem of QCD. At Stanford/SLAC, we are developing the Radio Frequency Quantum Upconverter (RQU) [1], a Josephson-junction-based device capable of measuring low-frequency electromagnetic signals more sensitively than the Standard Quantum Limit. In particular, these sensors will be used to search for QCD axion dark matter in the Dark Matter Radio experiment at masses from 1neV to 1 μeV (300kHz – 300MHz). The RQU is a quantum sensor capable of implementing multiple quantum coherent measurement techniques below 300 MHz, including two-mode squeezing, sideband cooling, and backaction evasion. I will describe the implementation of an RQU with superconducting microwave circuit elements and quantum coherent measurement protocols appropriate for ultra-light axion dark matter detection

[1] Stephen E. Kuenstner et al, arXiv:2210.05576.

Keywords: superconducting quantum sensor, Josephson-junction-based device, dark matter detection, quantum chromodynamics axion