After a coordinate transformation, the wavefunction of the ground state of the fractional Quantum Hall Effect is found to be the congregation of free independent particles immune to thermal phonon disturbance. Based on the pseudo-spin states appearing in the two layer system of fractional Quantum Hall Effect, we propose a new controlled NOT gate with very large decoherence time.

Theoretical considerations show that superconductive granular films can be classified into two groups; \varTheta-superconductors with a definitive phase and N-superconductors with a definitive particle number. It is pointed out that a device made of an N-supercnductor has properties conjugate to the Josephson effect.

We observed in highly resistive NbN thin films at low temperature dual conduction characteristics in clearly separated two region of their sheet resistance. In the specimens with R□<Rc the conduction characteristics are well explained by Kosterlitz-Thouless (KT) effect for flux-soliton pairs. In the specimens with R□>Rc, however, the conduction characteristics can be explained supposing the KT effect for charge-soliton pairs.

Sinusoidal conductivity variation is observed in highly resistive granular NbN thin films when an external electric field is applied perpendicular to the film surface at low temperatures. The electric charge necessary to make 1 cycle of conductivity variation is estimated to be about electron pair charge 2e.

The electrical field effect of highly resistive BiSrCaCuO granular thin films was studied. In order to form a uniform granular structure, BiSrCaCuO thin films where deposited on SrTiO3(110) substrates. When the films have relatively high room-temperature sheet resistance, the insulating transition at low temperatures and the charging effect are observed, which may be due to the single-electron tunneling effect in the array of small intergrain junctions.