Rydberg-atom-based single-photon detection for haloscope axion searches

We propose a Rydberg-atom-based single-photon detector for signal readout in dark matter haloscope experiments between <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mn>40</a:mn><a:mtext> </a:mtext><a:mtext> </a:mtext><a:mi mathvariant="normal">μ</a:mi><a:mi>eV</a:mi></a:mrow></a:math> and <d:math xmlns:d="http://www.w3.org/1998/Math/MathML" display="inline"><d:mrow><d:mn>200</d:mn><d:mtext> </d:mtext><d:mtext> </d:mtext><d:mi mathvariant="normal">μ</d:mi><d:mi>eV</d:mi></d:mrow></d:math> (10 GHz and 50 GHz). At these frequencies, standard haloscope readout using linear amplifiers is limited by quantum measurement noise, which can be avoided by using a single-photon detector. Our single-photon detection scheme can offer scan rate enhancements up to a factor of <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:mrow><g:msup><g:mrow><g:mn>10</g:mn></g:mrow><g:mrow><g:mn>4</g:mn></g:mrow></g:msup></g:mrow></g:math> over traditional linear amplifier readout, and is compatible with many different haloscope cavities. We identify multiple haloscope designs that could use our Rydberg-atom-based single-photon detector to search for QCD axions with masses above <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"><i:mrow><i:mn>40</i:mn><i:mtext> </i:mtext><i:mtext> </i:mtext><i:mi mathvariant="normal">μ</i:mi><i:mi>eV</i:mi></i:mrow></i:math> (10 GHz), currently a minimally explored parameter space. Published by the American Physical Society 2024