Jul 5 – 12, 2017
Venice, Italy
Europe/Zurich timezone
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Possible resonance effect of dark matter axions in SNS Josephson junctions

Jul 7, 2017, 12:45 PM
Room Mosaici-2 (Palazzo del Casinò)

Room Mosaici-2

Palazzo del Casinò

Parallel Talk Dark Matter Dark matter


Prof. Christian Beck (Queen Mary, University of London)


Dark matter axions can generate peculiar effects in special types of Josephson junctions, so-called SNS junctions [1]. One can show that the axion field equations in a Josephson environment allow for very small oscillating supercurrents, which manifest themselves as a tiny wiggle in the I-V curve, a so-called Shapiro step, which occurs at a frequency given by the axion mass. The effect is very small but perfectly measurable in modern nanotechnological devices. In this talk I will summarize the theory and then present evidence that candidate Shapiro steps of this type have indeed been seen in several independent experiments [2]. Assuming the observed tiny Shapiro steps are due to axion flow then these data consistently point to an axion mass of about 110 $\mu$eV, consistent with what is expected for the QCD axion. In addition to the above small Shapiro resonance effects at frequencies in the GHz region one also expects to see broad-band noise effects at much lower frequencies [3]. Overall this approach provides a novel pathway for the future design of new types of axionic dark matter detectors.

[1] C. Beck, Possible resonance effect of axionic dark matter in Josephson junctions, Phys. Rev. Lett. 111, 231801 (2013)

[2] C. Beck, Axion mass estimates from resonant Josephson junctions, Phys. Dark Univ. 7-8, 6-11 (2015)

[3] C. Beck, Cosmological flux noise and measured noise power spectra in SQUIDs,
Scient. Rep. 6, 28275 (2016)

Primary author

Prof. Christian Beck (Queen Mary, University of London)

Presentation materials