In 1962 Brian Josephson predicted that a current of superconducting electron pairs could tunnel through an insulating junction between two superconductors while maintaining the phase coherence of the pairs’ wavefunctions on the two sides of the junction; the effect was soon experimentally verified. Such Josephson junctions can switch rapidly to the resistive state and have very low power dissipation, properties that suggest the application of Josephson junctions to computers. IBM started investigating superconducting computers, using Josephson junctions for memories and logic circuits, in 1964. Juri Matisoo and his colleagues at IBM demonstrated a logic circuit with subnanosecond operation in 1966. At the time, this switching speed was very attractive, for it indicated that Josephson devices could be competitive with semiconductor devices.
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March 1986
March 01 1986
Josephson Computer Technology Available to Purchase
Recent advances on the road to superconducting computers include novel operating designs for logic and memory circuits as well as stable and reliable devices made entirely from refractory materials.
Physics Today 39 (3), 46–52 (1986);