Motlakunta Sainath, Kotibhaskar Nikhil, Shih Chung-You, Vogliano Anthony, McLaren Darian, Hahn Lewis, Zhu Jingwen, Hablützel Roland, Islam Rajibul
Institute for Quantum Computing, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
Department of Physics and Astronomy, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
Nat Commun. 2024 Aug 3;15(1):6575. doi: 10.1038/s41467-024-50864-2.
Protecting qubits from accidental measurements is essential for controlled quantum operations, especially during state-destroying measurements or resets on adjacent qubits, in protocols like quantum error correction. Current methods to preserve atomic qubits against such disturbances waste coherence time, extra qubits, and introduce additional errors. We demonstrate the feasibility of in-situ state-reset and state-measurement of trapped ions, achieving >99.9% fidelity in preserving an 'asset' ion-qubit while a neighboring 'process' qubit is reset, and >99.6% preservation fidelity while applying a detection beam for 11 μs on the same neighbor at a distance of 6 μm. This is achieved through precise wavefront control of addressing optical beams and using a single ion as both a quantum sensor for optical aberrations and an intensity probe with >50 dB dynamic range. Our demonstrations advance quantum processors, enhancing speed and capabilities for tasks like quantum simulations of dissipation and measurement-driven phases, and implementing error correction.
对于受控量子操作而言，保护量子比特免受意外测量的影响至关重要，特别是在诸如量子纠错等协议中，在对相邻量子比特进行态破坏测量或重置期间。当前用于保护原子量子比特免受此类干扰的方法会浪费相干时间、额外的量子比特，并引入额外的误差。我们展示了捕获离子原位态重置和态测量的可行性，在相邻的“处理”量子比特被重置时，对“资产”离子量子比特的保真度保持在>99.9%，并且在距离为6μm的同一相邻量子比特上施加11μs检测光束时，保真度保持在>99.6%。这是通过对寻址光束进行精确的波前控制，并使用单个离子作为光学像差的量子传感器以及动态范围>50dB的强度探测器来实现的。我们的演示推动了量子处理器的发展，提高了诸如耗散和测量驱动相的量子模拟以及实现纠错等任务的速度和能力。
