title: High fidelity quantum state transfer in electromechanical systems with intermediate coupling.
abstract: Hybrid quantum systems usually consist of two or more subsystems, which may take the advantages of the different systems. Recently, the hybrid system consisting of circuit electromechanical subsystems have attracted great attention due to its advanced fabrication and scalable integrated photonic circuit techniques. Here, we propose a scheme for high fidelity quantum state transfer between a superconducting qubit and a nitrogen-vacancy center in diamond, which are coupled to a superconducting transmission-line resonator with coupling strength g1 and a nanomechanical resonator with coupling strength g2, respectively. Meanwhile, the two resonators are parametrically coupled with coupling strength J. The system dynamics, including the decoherence effects, is numerical investigated. It is found that both the small (J<<{g1,g2}) and large (J>>{g1,g2}) coupling regimes of this hybrid system can not support high fidelity quantum state transfer before significant technique advances. However, in the intermediate coupling regime (J ~ g1 ~ g2), in contrast to a conventional wisdom, high fidelity quantum information transfer can be implemented, providing a promising route towards high fidelity quantum state transfer in similar coupled resonators systems.
authors.affiliation: 1] Laboratory of Quantum Engineering and Quantum Materials, and School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006, China [2] Anhui Xinhua University, Hefei, 230088, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhou
authors.affiliation: 1] Department of Physics and Center of Theoretical and Computational Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, China [2] School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Zhang-qi
authors.initials: ZQ
authors.lastname: Yin
authors.affiliation: Department of Physics and Center of Theoretical and Computational Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
authors.forename: Z D
authors.initials: ZD
authors.lastname: Wang
authors.affiliation: National Laboratory of Solid State Microstructure and Department of Physics, Nanjing University, Nanjing 210093, China.
authors.forename: Shi-Liang
authors.initials: SL
authors.lastname: Zhu
authors.affiliation: 1] Laboratory of Quantum Engineering and Quantum Materials, and School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006, China [2] Department of Physics and Center of Theoretical and Computational Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
authors.forename: Zheng-Yuan
authors.initials: ZY
authors.lastname: Xue