Single qubit and its universal logic gate made of an annular spin cluster with anisotropic Heisenberg-chain

Abstract

We investigate an annular spin cluster made of three particles with anisotropic Heisenberg-chain controlled by a time-dependent magnetic field. The system has an SU(2) algebraic structure. Using algebraic dynamical method, we have obtained the exact analytical solution to the time dependent Schrdinger equation. Based on the analytical solution, it is shown that the system can be used as a universal single qubit logic gate controlled by the strength and frequency of the magnetic field, and consequently six special single qubit logic gates can be realized.