Charge state and phase state representations of bosonic Josephson qubit model for quantum computation

Abstract

Abstract By analogy with the number-difference-phase theory in quantum optics, we introduce nonlinear Bose operator to represent the phase across Josephson junction, and build a bosonic operator Josephson qubit model, which establish itself firmly on the ground of charge state representation and phase state representation. The operator version of Josephson equations are also obtained.