3rd Physics Institute, University of Stuttgart, Pfaffenwaldring 57, Stuttgart 70569, Germany.
Department of Chemistry, Technical University Munich, Lichtenbergstrasse 4, Garching 85747, Germany.
Nat Commun. 2016 Aug 10;7:12279. doi: 10.1038/ncomms12279.
In quantum sensing, precision is typically limited by the maximum time interval over which phase can be accumulated. Memories have been used to enhance this time interval beyond the coherence lifetime and thus gain precision. Here, we demonstrate that by using a quantum memory an increased sensitivity can also be achieved. To this end, we use entanglement in a hybrid spin system comprising a sensing and a memory qubit associated with a single nitrogen-vacancy centre in diamond. With the memory we retain the full quantum state even after coherence decay of the sensor, which enables coherent interaction with distinct weakly coupled nuclear spin qubits. We benchmark the performance of our hybrid quantum system against use of the sensing qubit alone by gradually increasing the entanglement of sensor and memory. We further apply this quantum sensor-memory pair for high-resolution NMR spectroscopy of single (13)C nuclear spins.
在量子传感中，精度通常受到相位可以累积的最大时间间隔的限制。存储器已被用于将此时间间隔延长到相干寿命之外，从而提高精度。在这里，我们证明通过使用量子存储器也可以实现更高的灵敏度。为此，我们使用了一种混合自旋系统中的纠缠，该系统包括一个与钻石中的单个氮空位中心相关联的传感和记忆量子位。通过使用存储器，即使在传感器的相干衰减之后，我们也能保留完整的量子态，从而实现与不同弱耦合核自旋量子位的相干相互作用。我们通过逐渐增加传感器和存储器的纠缠来对比单独使用传感量子位的情况下我们混合量子系统的性能。我们还进一步将这个量子传感器-存储器对应用于单个 (13)C 核自旋的高分辨率 NMR 光谱学中。
