Interferencing intensity in two Bose–Einstein condensates with Josephson-like coupling

We derive a general expression for interferencing intensity in two Bose–Einstein condensates with Josephson-like coupling when the two Bose–Einstein condensates are initially in arbitrary quantum pure states. The expression can be used to numerically calculate the intensity. As examples, we study the time behaviors of the intensity when the two Bose–Einstein condensates are initially in coherent states, Fock states, and squeezed states, respectively.