Two-mode excited entangled coherent states and their entanglement properties

This paper introduces two types of two-mode excited entangled coherent states (TMEECSs) $|\Psi_{\pm}(\alpha,m,n)\rangle$, studies their entanglement characteristics, and investigates the influence of photon excitations on quantum entanglement. It shows that for the state $|\Ps_{+}(\alpha,m,m)\rangle$ the two-mode photon excitations affect seriously entanglement character while the state $|\Ps_{-}(\alpha,m,m)\rangle$ is always a maximally entangled state, and shows how such states can be produced by using cavity quantum electrodynamics and quantum measurements. It finds that the entanglement amount of the TMEECSs is larger than that of the single-mode excited entangled coherent states with the same photon excitation number.