Transferring entangled states of photonic cat-state qubits in circuit QED

• Published in: Frontiers of physics Vol. 15; no. 2; p. 21603
• Main Authors: Liu, Tong, Zheng, Zhen-Fei, Zhang, Yu, Fang, Yu-Liang, Yang, Chui-Ping
• Format: Journal Article
• Language: English
• Published: Beijing Higher Education Press 01.04.2020; Springer Nature B.V
• Subjects: Astronomy; Astrophysics and Cosmology; Atomic; Circuits; Condensed Matter Physics; Couplers; Crosstalk; Energy levels; Entangled states; Error correction & detection; Holes; microwave cavities; Molecular; Optical and Plasma Physics; Particle and Nuclear Physics; photonic cat-state; Physics; Physics and Astronomy; Proposals; Quantum electrodynamics; Quantum entanglement; Qubits (quantum computing); Research Article; Resonators; transferring quantum entangled states; Transmission lines; photonic cat-state; transferring quantum entangled states; microwave cavities
• ISSN: 2095-0462; 2095-0470
• DOI: 10.1007/s11467-019-0949-5

We propose a method for transferring quantum entangled states of two photonic cat-state qubits ( cqubits) from two microwave cavities to the other two microwave cavities. This proposal is realized by using four microwave cavities coupled to a superconducting flux qutrit. Because of using four cavities with different frequencies, the inter-cavity crosstalk is significantly reduced. Since only one coupler qutrit is used, the circuit resource is minimized. The entanglement transfer is completed with a singlestep operation only, thus this proposal is quite simple. The third energy level of the coupler qutrit is not populated during the state transfer, therefore decoherence from the higher energy level is greatly suppressed. Our numerical simulations show that high-fidelity transfer of two- cqubits entangled states from two transmission line resonators to the other two transmission line resonators is feasible with current circuit QED technology. This proposal is universal and can be applied to accomplish the same task in a wide range of physical systems, such as four microwave or optical cavities, which are coupled to a natural or artificial three-level atom.