Magnetically switched quantum waveguide qubit

Recently, quantum computing has gained notoriety as a computational method that has the possibility to greatly increase the speed of calculations compared with traditional, binary computing. To this end, simulations of a quantum controlled-not gate implemented by a quantum waveguide are examined. The waveguide is composed of two quantum wires and a tuned coupling region and the simulations consist of a solution to Schrodinger's equation via the Usuki method of mode matching. The use of Gaussian wave packets in previous work on this topic is questioned and various methods of tuning the coupling region in order to guide the quantum wave are investigated. Simulations are shown for a tuned waveguide in which the wave can be switched by the application of an external magnetic field. (C) 2001 American Institute of Physics.