The Josephson effect on alternating currents, reported by predictions in 1962, and experimentally observed in 1963 in the form of “sudden quantum phases in electric potential” (Shapiro surges), by photon-assisted quantum tunneling of a pair of Cooper electrons, is It is one of the most fundamental phenomena in quantum mechanics, and is essential in setting quantitative standards for measuring electric potential. Researchers envision this dual physical effect; The effect of an abrupt coherence-wave quantum phase change within alternating currents (CQPS), coupled with the tunneling of magnetic fluxes through a photon-assisted superconducting nanowire, is represented by quantitatively occurring “gradients in current”. The very important physical significance of this physical effect is reinforced by its practical value in setting standards for future measurement of currents, which is a missing element needed to complete the quantum metrology triangle. It should be noted in this context that in 2012, it was demonstrated that this effect can be created in the form of a quantum of magnetic fluxes superimposed in superconducting nanowires. However, grading direct constant currents within superconductors, the only fundamental effect that scientists have been unable to achieve in superconducting states, has remained elusive due to a lack of suitable materials and challenges in circuit engineering.
In this published paper, the researchers report results from direct observations of the dual effect caused by Shapiro’s sudden (phase) changes in a superconducting nanowire. Abrupt phases were visible up to a frequency of 26 GHz with a current of 8.3 nA, and the bandwidth specified in the experiment limited them. It is true that sudden current phases were theoretically predicted in small Josephson-type connections 30 years ago, but the expansion of Josephson connections is inevitable, preventing these phases from being directly observed with practical experiments. Then, the research team solves this problem by installing a thin nanowire of niobium nitride in an environment that affects this phenomenon.