On Effectiveness of Protocol Creating Maximum Entanglement of Two Charge-Phase Qubits by C

On Effectiveness of Protocol Creating Maximum Entanglement of Two Charge-Phase Qubits by

Cavity Field

佚名

【期刊名称】《理论物理通讯（英文版）》 【年(卷),期】2007(048)011

【摘要】We revisit the protocols to create maximally entangled states between two Josephson junction (JJ) charge phase qubits coupled to a microwave field in a cavity as a quantum data bus. We analyze a novel mechanism of quantum decoherence due to the adiabatic entanglement between qubits and the data bus, the off-resonance microwave field. We show that even if the variable of the data bus can be adiabatically eliminated, the entanglement between the qubits and data bus remains and can decohere the superposition of two-particle state. Fortunately we can construct a decoherencefree subspace of two-dimension to against this adiabatic decoherence. To carry out the analytic study for this decoherence problem, we develop Fr(o)hlich transformation to re-derive the effective Hamiltonian of these systems, which is equivalent to that obtained from the adiabatic elimination approach.

【总页数】8页(935-942)

【关键词】SQUID, quantum entanglement, conccurrence, decoherence