Nuclear Josephson junction.
The Josephson effect is a quantum phenomenon appearing in superconductors.
It consists in the spontaneous flow of electric current, due to tunneling, between the two
superconductors separated by a thin insulator layer. The current flow is induced by
phase difference of wave functions describing superconducting electrons on both
sides of the insulator. This is called the Josephson junction.
The phenomenon occurs in metals as well as in ultracold atomic gases.
Search for the Josephson effect in nuclear systems
have been going on for almost half a century.
Theoretical analysis of recent experiments involving collisions of Nickel-60 and Tin-116
provided strong arguments for creation of the Josephson junction.
Contrary to the previous measurements where
the pair transfer cross section has been investigated, this time the gamma radiation spectrum
was analyzed. It turned out that the spectrum of emitted gamma rays agrees with the theoretical
predictions assuming the formation of the so-called AC Josephson junction.
Piotr Magierski
The Tiniest Superfluid Circuit in Nature
Physics 14, 27 (2021)