Remote Generation of Magnon Schrödinger Cat State via Magnon-Photon Entanglement

• Published in: Physical review letters 2021-08, Vol.127 (8), p.1-087203, Article 087203
• Main Authors: Sun, Feng-Xiao, Zheng, Sha-Sha, Xiao, Yang, Gong, Qihuang, He, Qiongyi, Xia, Ke
• Format: Article
• Language: English
• Subjects: Data processing; Error analysis; Magnons; Photons; Quantum computing; Quantum entanglement; Quantum mechanics; Quantum phenomena; Schroedinger cat state
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/PhysRevLett.127.087203

The magnon cat state represents a macroscopic quantum superposition of collective magnetic excitations of large number spins that not only provides fundamental tests of macroscopic quantum effects but also finds applications in quantum metrology and quantum computation. In particular, remote generation and manipulation of Schrödinger cat states are particularly interesting for the development of long-distance and large-scale quantum information processing. Here, we propose an approach to remotely prepare magnon even or odd cat states by performing local non-Gaussian operations on the optical mode that is entangled with the magnon mode through pulsed optomagnonic interaction. By evaluating key properties of the resulting cat states, we show that for experimentally feasible parameters, they are generated with both high fidelity and nonclassicality, as well as with a size large enough to be useful for quantum technologies. Furthermore, the effects of experimental imperfections such as the error of projective measurements and dark count when performing single-photon operations have been discussed, where the lifetime of the created magnon cat states is expected to be t ∼ 1     μ s .