Kaufmann H, Ruster T, Schmiegelow C T, Luda M A, Kaushal V, Schulz J, von Lindenfels D, Schmidt-Kaler F, Poschinger U G
Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany.
Phys Rev Lett. 2017 Oct 13;119(15):150503. doi: 10.1103/PhysRevLett.119.150503.
We demonstrate the deterministic generation of multipartite entanglement based on scalable methods. Four qubits are encoded in ^{40}Ca^{+}, stored in a microstructured segmented Paul trap. These qubits are sequentially entangled by laser-driven pairwise gate operations. Between these, the qubit register is dynamically reconfigured via ion shuttling operations, where ion crystals are separated and merged, and ions are moved in and out of a fixed laser interaction zone. A sequence consisting of three pairwise entangling gates yields a four-ion Greenberger-Horne-Zeilinger state |ψ⟩=(1/sqrt[2])(|0000⟩+|1111⟩), and full quantum state tomography reveals a state fidelity of 94.4(3)%. We analyze the decoherence of this state and employ dynamic decoupling on the spatially distributed constituents to maintain 69(5)% coherence at a storage time of 1.1 sec.
我们展示了基于可扩展方法确定性地生成多体纠缠。四个量子比特编码在(^{40}Ca^{+})中，存储在一个微结构分段保罗阱中。这些量子比特通过激光驱动的成对门操作依次纠缠。在此期间，量子比特寄存器通过离子穿梭操作进行动态重新配置，其中离子晶体被分离和合并，并且离子移入和移出固定的激光相互作用区域。由三个成对纠缠门组成的序列产生一个四离子格林伯格 - 霍恩 - 蔡林格态(\vert\psi\rangle=(1/\sqrt{2})(\vert0000\rangle+\vert1111\rangle))，并且全量子态断层扫描显示态保真度为94.4(3)%。我们分析了该状态的退相干，并对空间分布的成分采用动态解耦，以在1.1秒的存储时间内保持69(5)%的相干性。
