论文标题
用量子组合来表征温度和应变变化，以保护其强大的连贯性保护
Characterizing temperature and strain variations with qubit ensembles for their robust coherence protection
论文作者
论文摘要
固态自旋缺陷，尤其是具有可实现的长相干时间的核自旋，是量子记忆和传感器的诱人候选者。但是，由于它们的内在四极杆和超细相互作用的变化，它们的当前性能仍受到逆转的限制。我们提出了一个\ textit {不平衡的echo}来克服这一挑战，通过使用第二个旋转来重新聚焦这些相互作用的变化，从而保留了存储在自由进化中的量子信息。不平衡的回声可用于探测材料中的温度和应变分布。在实验上，我们证明了$ \ sim10^{10} $核自旋的合奏中的20倍$ T_2^*$相干时间增加。从理论上讲，我们开发了第一原理方法来预测这些相互作用的变化并在大温度和应变范围内揭示它们的相关性。我们从数值上表明，与当前的实验相比，我们的方法可以重新调整更强的噪声变化，并在25〜K温度不均匀的情况下实现400倍的相干性改善。
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 the decoherence due to the variation of their intrinsic quadrupole and hyperfine interactions. We propose an \textit{unbalanced echo} to overcome this challenge by using a second spin to refocus the variation of these interactions, which preserves the quantum information stored in the free evolution. The unbalanced echo can be used to probe the temperature and strain distribution in materials. Experimentally, we demonstrate a 20-fold $T_2^*$ coherence time increase in an ensemble of $\sim10^{10}$ nuclear spins in diamond. Theoretically, we develop first-principles methods to predict these interaction variations and reveal their correlation in large temperature and strain ranges. We numerically show that our method can refocus stronger noise variations than our current experiments and achieves a 400-fold coherence improvement for a 25~K temperature inhomogeneity.
