"In summary, the vacuum polarization alters the Josephson frequency-voltage relation in the presence of a strong magnetic field and results in a weak dependence of the Josephson constant on the magnetic field strength. This remarkable manifestation of a fine nonlinear quantum field effect in a collective phenomenon in condensed matter could be observed in a dedicated experiment, that would literally be a measurement of the vacuum polarization with a voltmeter."
Phys. Rev. Lett. 104, 097003 (2010) [4 pages]
Measuring Vacuum Polarization with Josephson Junctions
Received 19 October 2009; published 5 March 2010
We argue that the vacuum polarization by the virtual electron-positron pairs can be measured by studying a Josephson junction in a strong magnetic field. The vacuum polarization results in a weak dependence of the Josephson constant on the magnetic field strength which is within the reach of the existing experimental techniques.
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