The charge, Q, resulting from this current shifts θ and the ground state to a new, degenerate, ground state. Thus, a vacuum with 〈 θ 〉 = 0 will shift to a different vacuum with 〈 θ 〉 = ε. The current connects the original vacuum with the Nambu–Goldstone boson state, 〈0| J 0 (0)| θ 〉≠ 0.