Anomaly in superconductor experiment may have been dark matter

Ars Technica : A 2004 experiment that studied noise in Josephson junctions —thinly separated superconductors that exchange electron pairs—found a spike in the noise that could not be explained by any current superconductor theories. Now, Christian Beck of the University of Cambridge has proposed that the spike was caused by the presence of axions—a possible form of dark matter—that transformed into photons inside the junction, which amplified the signal at a specific frequency. Axions are very low mass, electrically neutral particles originally proposed to explain the CP violation problem associated with quantum chromodynamics , the theory that describes the strong force. Unlike neutrinos, which are similarly low mass and electrically neutral, axions would exist in such large number that they could be an alternative to weakly interacting massive particles (WIMPs) for explaining dark matter. Although axions have not yet been detected, if Beck’s theory is correct, then the spike should be easy to replicate. And because of the simplicity of the Josephson junction setup, it should be easy to determine if there is some other source for the signal.