Multipartite entanglement in the interaction system between a single-mode microwave cavity field and superconducting charge qubits

This paper proposes a method of generating multipartite entanglement through usingd.c. superconducting quantum interference devices (SQUID) inside a standingwave cavity. In this scheme, the d.c. SQUID works in the charge region. Itis shown that, a large number of important multipartite entangled states canbe generated by a controllable interaction between a cavity field andqubits. It is even possible to produce entangled states involving differentcavity modes based on the measurement of charge qubits states. After suchsuperpositions states are created, the interaction can be switched off bythe classical magnetic field through the SQUID, and there is no informationtransfer between the cavity field and the charge qubits.