No abstract

We propose a novel scheme for generating 𝑁 -qubit GHZ entangled state with a hybrid quantum system, which consists of 𝑁 nitrogen-vacancy centers, 𝑁 transmission line resonators, a current-biased Josephson junction superconducting qubit, and three kinds of interaction Hamiltonians. The proposal requires no adjustment of the qubit level spacings during the entire operation. Moreover, it is shown that the operation time is independent of the number of qubits. The present proposal is quite useful, and is a promising step to realize the large-sized quantum networks for quantum information processing and quantum computation.

We put forward a scheme for quantum teleportation of continuous-variable Gaussian states using, as a quantum channel, a two-mode squeezed vacuum interacting with a thermal environment showing memory effects. We found that fidelity larger than the classical limit may be obtained, upon exploiting memory effects, also using lower measurement gain. We show that fidelity increases with the memory of the channel and decreases with the thermal noise. Finally, we discuss the effects of memory on the distortion cumulants.

We study the entanglement dynamics between two strongly-AC-driven superconducting charge qubits coupled collectively to a zero temperature, dissipative resonator and find an unusual feather that the competing of creation and annihilation of entanglement can lead to entanglement increasing, sudden death and revival. We also calculate the dependence of the death time on the initial state of the system.