Abstract: A vertical Hall device includes: a substrate; a semiconductor region having a first conductive type and disposed in the substrate; and a magnetic field detection portion disposed in the semiconductor region. The magnetic field detection portion is capable of detecting a magnetic field parallel to a surface of the substrate in a case where a current flows through the magnetic field detection portion in a vertical direction of the substrate. The semiconductor region is a diffusion layer including a conductive impurity doped and diffused therein. The semiconductor region is made of diffusion layer so that the device has high design degree of freedom.

Abstract: A quantum computer can only function stably if it can execute gates with extreme accuracy. “Topological protection” is a road to such accuracies. Quasi-particle interferometry is a tool for constructing topologically protected gates. Assuming the corrections of the Moore-Read Model for v= 5/2's FQHE (Nucl. Phys. B 360, 362 (1991)) we show how to manipulate the collective state of two e/4-charge anti-dots in order to switch said collective state from one carrying trivial SU(2) charge, |1>, to one carrying a fermionic SU(2) charge |?>. This is a NOT gate on the {|1>, |?>} qubit and is effected by braiding of an electrically charged quasi particle ? which carries an additional SU(2)-charge. Read-out is accomplished by ?-particle interferometry.