Re: Quantum Computers

Patrick Wilken (
Sat, 21 Aug 1999 09:55:33 +1000

SW BULLETIN - August 20, 1999

In a quantum computer, information is stored via quantum variables such as spins, photons, or atoms. The elementary unit is a two-state quantum system called a "qubit". Electron beam lithography is a lithographic method in which a radiationsensitive film is exposed to a computer controlled electron beam; the method can be applied to the microdesign of circuits. In general, a Josephson junction is a thin insulator separating two superconductors. J.E. Mooij et al (NL US) now report the design of a qubit that can be fabricated with conventional electron beam lithography and which is suited for integration into a large quantum computer. The qubit consists of a micron-sized loop with 3 or 4 Josephson junctions, the 2 qubit states having persistent currents of opposite direction. The authors suggest that apart from its quantum computing potential, the proposed qubit should be of considerable interest for fundamental studies of macroscopic quantum coherence. (SCI)

Patrick Wilken
Editor:        PSYCHE: An International Journal of Research on Consciousness
Board Member:      The Association for the Scientific Study of Consciousness