Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, USA.
Tabor Electronics, Inc., Hatasia 9, Nesher 3660301, Israel.
Phys Rev Lett. 2021 Oct 22;127(17):170603. doi: 10.1103/PhysRevLett.127.170603.
We report the observation of long-lived Floquet prethermal states in a bulk solid composed of dipolar-coupled ^{13}C nuclei in diamond at room temperature. For precessing nuclear spins prepared in an initial transverse state, we demonstrate pulsed spin-lock Floquet control that prevents their decay over multiple-minute-long periods. We observe Floquet prethermal lifetimes T_{2}^{'}≈90.9 s, extended >60 000-fold over the nuclear free induction decay times. The spins themselves are continuously interrogated for ∼10 min, corresponding to the application of ≈5.8×10^{6} control pulses. The ^{13}C nuclei are optically hyperpolarized by lattice nitrogen vacancy centers; the combination of hyperpolarization and continuous spin readout yields significant signal-to-noise ratio in the measurements. This allows probing the Floquet thermalization dynamics with unprecedented clarity. We identify four characteristic regimes of the thermalization process, discerning short-time transient processes leading to the prethermal plateau and long-time system heating toward infinite temperature. This Letter points to new opportunities possible via Floquet control in networks of dilute, randomly distributed, low-sensitivity nuclei. In particular, the combination of minutes-long prethermal lifetimes and continuous spin interrogation opens avenues for quantum sensors constructed from hyperpolarized Floquet prethermal nuclei.
我们在室温下的钻石中发现了由偶极耦合^{13}C 核组成的块状固体中的长寿命弗洛凯预热态。对于初始横向状态下的进动核自旋，我们演示了脉冲自旋锁定弗洛凯控制，防止它们在多个分钟长的时间段内衰减。我们观察到弗洛凯预热寿命 T_{2}^{'}≈90.9 s，比核自由感应衰减时间延长了>60 000 倍。自旋本身被连续探测了约 10 min，对应于施加了约 5.8×10^{6}个控制脉冲。^{13}C 核通过晶格氮空位中心光学超极化；极化和连续自旋读出的结合在测量中产生了显著的信噪比。这使得可以以前所未有的清晰度探测弗洛凯热化动力学。我们确定了热化过程的四个特征区域，分辨出导致预热平台的短时间瞬态过程和朝向无限温度的长时间系统加热。这封信指出了通过稀释、随机分布、低灵敏度核的弗洛凯控制可能带来的新机会。特别是，预热寿命长达几分钟和连续自旋探测的结合为基于超极化弗洛凯预热核的量子传感器开辟了途径。
