Before revision: The major distinction among the three is the ratio of Josephson energy vs (Coulomb) charge energy: For phase qubit , this ratio is on the order of , whereas for flux qubit it's on the order of 10, and for charge qubit less than 1.
After revision: 106The major distinction among the three is the ratio of Josephson energy vs (Coulomb) charge energy: For phase qubit , this ratio is on the order of , whereas for flux qubit it's on the order of 10, and for charge qubit less than 1.