  We present a theoretical proposal for a physical implementation of
entanglement concentration and purification protocols for two-mode squeezed
microwave photons in circuit quantum electrodynamics (QED). First, we give the
description of the cross-Kerr effect induced between two resonators in circuit
QED. Then we use the cross-Kerr media to design the effective quantum
nondemolition (QND) measurement on microwave-photon number. By using the QND
measurement, the parties in quantum communication can accomplish the
entanglement concentration and purification of nonlocal two-mode squeezed
microwave photons. We discuss the feasibility of our schemes by giving the
detailed parameters which can be realized with current experimental technology.
Our work can improve some practical applications in continuous-variable
microwave-based quantum information processing.
