Transfer of quantum entangled states between superconducting qubits and microwave field qubits

• Published in: Frontiers of physics Vol. 17; no. 6; p. 61502
• Main Authors: Liu, Tong, Guo, Bao-Qing, Zhou, Yan-Hui, Zhao, Jun-Long, Fang, Yu-Liang, Wu, Qi-Cheng, Yang, Chui-Ping
• Format: Journal Article
• Language: English
• Published: Beijing Higher Education Press 01.12.2022; Springer Nature B.V
• Subjects: Astronomy; Astrophysics and Cosmology; Atomic; circuit QED; Circuits; Coding; coherent states; Condensed Matter Physics; Data processing; Energy levels; Entangled states; Holes; microwave field qubits; Molecular; Optical and Plasma Physics; Particle and Nuclear Physics; Physics; Physics and Astronomy; Quantum dots; Quantum electrodynamics; Quantum entanglement; Quantum mechanics; Quantum phenomena; Quantum theory; Qubits (quantum computing); Research Article; superconducting qubits; Superconductivity; tranferring entangled states; superconducting qubits; microwave field qubits; coherent states; tranferring entangled states; circuit QED
• ISSN: 2095-0462; 2095-0470
• DOI: 10.1007/s11467-022-1166-1

Transferring entangled states between matter qubits and microwave-field (or optical-field) qubits is of fundamental interest in quantum mechanics and necessary in hybrid quantum information processing and quantum communication. We here propose a way for transferring entangled states between superconducting qubits (matter qubits) and microwave-field qubits. This proposal is realized by a system consisting of multiple superconducting qutrits and microwave cavities. Here, qutrit refers to a three-level quantum system with the two lowest levels encoding a qubit while the third level acting as an auxiliary state. In contrast, the microwave-field qubits are encoded with coherent states of microwave cavities. Because the third energy level of each qutrit is not populated during the operation, decoherence from the higher energy levels is greatly suppressed. The entangled states can be deterministically transferred because measurement on the states is not needed. The operation time is independent of the number of superconducting qubits or microwave-field qubits. In addition, the architecture of the circuit system is quite simple because only a coupler qutrit and an auxiliary cavity are required. As an example, our numerical simulations show that high-fidelity transfer of entangled states from two superconducting qubits to two microwave-field qubits is feasible with present circuit QED technology. This proposal is quite general and can be extended to transfer entangled states between other matter qubits (e.g., atoms, quantum dots, and NV centers) and microwave- or optical-field qubits encoded with coherent states.