WOLFRAM|DEMONSTRATIONS PROJECT

DC and AC Josephson Effects

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barrier opacity
RF amplitude
RF frequency
The upper graphic shows a Josephson junction: two superconductors, shown in gray, separated by a thin insulating barrier, all immersed in a liquid-helium cryostat. The junction is subjected to a DC voltage
V
0
as well as a much lower-amplitude high-frequency AC voltage, produced by radio frequency (RF) radiation. The current
I
through the junction is monitored. By varying the AC amplitude and voltage, as well as the barrier opacity, both the DC and the AC Josephson effects can be exhibited on the oscilloscope in the lower graphic. In an actual oscilloscope, the green traces would actually be more jagged, due to electronic noise.