利用破坏对称性的超导人造原子制备χ型四比特纠缠态

提出了利用在一维传输线共振器中的破坏对称性的超导人造原子来制备χ型四比特纠缠态的方案. 方案中所用到的Δ型三能级人造原子不同于自然的原子, 它可以产生循环跃迁. 经过适当时间的相互作用和简单的操作, 可以得到想要制备的纠缠态. 由于人造原子的激发态和光子态被绝热消除, 所以该方案对于人造原子的自发辐射和传输线共振器的衰减是鲁棒的.

The χ-type four-particle entangled state generated by using superconducting artificial atoms with broken symmetry

We propose a scheme for generating a genuine χ-type four-particle entangled state of superconducting artificial atoms with broken symmetry by using one-dimensional transmission line resonator as a data bus. With the help of the Circuit quantum electrodynamics system composed of Δ-type three-level artificial atoms and transmission line resonator, our scheme also has long coherence time and storage time. Meanwhile, the Δ-type three-level artificial atom used in the scheme is different from natural atom and has cyclic transitions. Furthermore, our scheme is easy to control and flexible. Through a suitable choice of the Rabi frequencies and detunings of the classical fields, we can use this system to implement the selective coupling between two arbitrary qubits. After suitable interaction time and simple operations, the desired entangled state can be obtained. Since artificial atomic excited states and photonic states are adiabatically eliminated, our scheme is robust against the spontaneous emissions of artificial atoms and the decays of transmission line resonator. We also analyze the performance and the experimental feasibility of the scheme, and show that our scheme is feasible under existing experimental conditions.