  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 $g_1$ and a nanomechanical resonator with coupling
strength $g_2$, 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
($J \ll \{g_1, g_2\}$) and large ($J \gg \{g_1, g_2\}$) coupling regimes of
this hybrid system can not support high fidelity quantum state transfer before
significant technique advances. However, in the intermediate coupling regime
($J \sim g_1 \sim g_2$), 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.

Quantum Physics