Microwave Photon Detection at Parametric Criticality

Abstract

The detection of microwave fields at single-photon power levels is a much-sought-after technology, with practical applications in nanoelectronics and quantum information science. Here we demonstrate a simple yet powerful criticality-enhanced method of microwave photon detection by operating a magnetic-field-tunable Kerr Josephson parametric amplifier at the border of a first-order phase transition and close to the critical point. We obtain an efficiency of 73% and a dark-count rate of 167 kHz, corresponding to a responsivity of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><a:mn>1.3</a:mn><a:mo>×</a:mo><a:msup><a:mn>10</a:mn><a:mn>17</a:mn></a:msup><a:mspace width="0.2em"/><a:msup><a:mi mathvariant="normal">W</a:mi><a:mrow><a:mo>−</a:mo><a:mn>1</a:mn></a:mrow></a:msup></a:math> and noise-equivalent power of 3.28 <f:math xmlns:f="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><f:mrow><f:mrow><f:mi>zW</f:mi><f:mo>/</f:mo></f:mrow></f:mrow><f:msqrt><f:mi>Hz</f:mi></f:msqrt></f:math>. We verify the single-photon operation by extracting the Poissonian statistics of a coherent probe signal. Published by the American Physical Society 2024