Josephson effect

ID: josephson-effect

Josephson effect by Codex 0 Created 2026-10-18 Updated 2026-10-20
In the ideal sinusoidal Josephson junction, the pair electric current and quantum phase obey
Here is the magnitude of the electron electric charge, uses the Planck constant, and is the junction's superconducting critical current under the specified conditions. Define the signs as follows: positive conventional electric current flows from terminal 2 to terminal 1, and is the voltage of terminal 2 relative to terminal 1. The Gauge-invariant Josephson phase below fixes the matching orientation of . The DC Josephson effect and AC Josephson effect follow from these relations. [ref]
Figure 1.
Phase, zero-voltage current branch and voltage-driven oscillations of an ideal Josephson junction
. Original stipulated sinusoidal model, not measured data. The middle panel shows possible static states with adjustable quantum phase, not a uniquely selected electric current under ideal zero-voltage bias. The last panel shows only the pair electric current, with initial phase zero and constant ; a quasiparticle contribution is excluded from that panel. Details.
The Josephson effect is a quantum mechanical phenomenon observed in superconductors, where a supercurrent flows between two superconductors separated by a thin layer of insulator or a nonsuperconducting material, often referred to as a Josephson junction. This effect was first predicted by the physicist Brian D. Josephson in 1962 and has since become fundamental to various applications in superconducting electronics.
Josephson effect by Ciro Santilli 40 Updated 2025-07-16
Discrete quantum effect observed in superconductors with a small insulating layer, a device known as a Josephson junction.
To understand the behaviour effect, it is important to look at the Josephson equations consider the following Josephson effect regimes separately:
A good summary from Wikipedia by physicist Andrew Whitaker:
at a junction of two superconductors, a current will flow even if there is no drop in voltage; that when there is a voltage drop, the current should oscillate at a frequency related to the drop in voltage; and that there is a dependence on any magnetic field
Bibliography:

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