Wang Guoqing, Barr Ariel Rebekah, Tang Hao, Chen Mo, Li Changhao, Xu Haowei, Stasiuk Andrew, Li Ju, Cappellaro Paola
Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Phys Rev Lett. 2023 Jul 28;131(4):043602. doi: 10.1103/PhysRevLett.131.043602.
Solid-state spin defects, especially nuclear spins with potentially achievable long coherence times, are compelling candidates for quantum memories and sensors. However, their current performances are still limited by dephasing due to variations of their intrinsic quadrupole and hyperfine interactions. We propose an unbalanced echo to overcome this challenge by using a second spin to refocus variations of these interactions while preserving the quantum information stored in the nuclear spin free evolution. The unbalanced echo can be used to probe the temperature and strain distribution in materials. We develop first-principles methods to predict variations of these interactions and reveal their correlation over large temperature and strain ranges. Experiments performed in an ensemble of ∼10^{10} nuclear spins in diamond demonstrate a 20-fold dephasing time increase, limited by other noise sources. We further numerically show that our method can refocus even stronger noise variations than present in our experiments.
固态自旋缺陷，尤其是具有潜在可实现的长相干时间的核自旋，是量子存储器和传感器极具吸引力的候选对象。然而，由于其固有四极相互作用和超精细相互作用的变化，它们目前的性能仍然受到退相的限制。我们提出一种不平衡回波，通过使用第二个自旋来重新聚焦这些相互作用的变化，同时保留存储在核自旋自由演化中的量子信息，以克服这一挑战。不平衡回波可用于探测材料中的温度和应变分布。我们开发了第一性原理方法来预测这些相互作用的变化，并揭示它们在大温度和应变范围内的相关性。在金刚石中约10^{10}个核自旋的集合中进行的实验表明，退相时间增加了20倍，受其他噪声源限制。我们进一步通过数值计算表明，我们的方法甚至可以重新聚焦比我们实验中更强的噪声变化。
