Complete Bell state measurement of diamond nuclear spins under a complete spatial symmetry at zero magnetic field
Complete Bell state measurement of diamond nuclear spins under a complete spatial symmetry at zero magnetic field
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DOI：
10.1063/5.0088155
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发表时间：
2022-05
影响因子：
4
通讯作者：
Raustin Reyes;Takaya Nakazato;Nobuaki Imaike;K. Matsuda;K. Tsurumoto;Y. Sekiguchi;H. Kosaka
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文献类型：
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作者：
Raustin Reyes;Takaya Nakazato;Nobuaki Imaike;K. Matsuda;K. Tsurumoto;Y. Sekiguchi;H. Kosaka
自旋量子比特所处空间的对称性在量子纠缠的操纵中起着至关重要的作用，量子纠缠控制着量子信息系统的性能。施加磁场，这通常是必要的自旋操纵和读出，不可避免地打破了空间对称性，诱导内部和外部场之间的量子化轴之间的竞争，从而限制了纠缠的纯度。如果我们能够在零磁场下操纵和读出纠缠，我们将能够避免量子化轴之间的竞争，以实现理想的高保真度。我们在这里展示了完整的贝尔态测量，这是量子处理的核心要素，在金刚石氮空位中心附近的两个碳核自旋。该演示是通过基于几何相位的完整纠缠操纵与极化微波在零磁场下，其中量子化轴是唯一定义的超精细场。即使在磁场不能应用于超导和自旋量子位的集成时，所展示的方案也允许高保真纠缠处理，从而为构建容错分布式量子计算机和量子中继器网络铺平了道路。
The symmetry of the space where a spin qubit resides plays an essential role in the manipulation of quantum entanglement, which governs the performance of quantum information systems. Application of a magnetic field, which is usually necessary for spin manipulation and readout, inevitably breaks the spatial symmetry to induce competition among quantization axes between internal and external fields, thus limiting the purity of the entanglement. If we could manipulate and readout entanglement under a zero magnetic field, we would be able to avoid the competition among quantization axes to achieve ideally high fidelity. We here demonstrate the complete Bell state measurement, which is a core element of quantum processing, of two carbon nuclear spins in the vicinity of a diamond nitrogen-vacancy center. The demonstration was made possible by holonomic entanglement manipulations based on the geometric phase with a polarized microwave under a zero magnetic field, where the quantization axis is uniquely defined by the hyperfine field. The demonstrated scheme allows high-fidelity entanglement processing even when magnetic fields cannot be applied to the integration of superconducting and spin qubits, thereby paving the way for building fault-tolerant distributed quantum computers and quantum repeater networks.