Josephson Effect

Superconductivity · 1962

Equation: I = I_c·sin(φ₁ − φ₂)
Field: Superconductivity
Named After: Brian Josephson
Year: 1962

Symbols

I supercurrent through a thin insulating barrier · I_c the junction's critical current · φ₁, φ₂ quantum phases of the superconductors on each side

Significance

Current flows through an insulator with no voltage at all, steered only by quantum phase — predicted by a 22-year-old graduate student. Josephson junctions are the working element of SQUID magnetometers, the definition of the volt, and the superconducting qubits inside today's quantum computers.