How much time does a tunneling particle spend in a barrier? A Larmor clock, one proposal to answer this question, measures the interaction between the particle and the barrier region using an auxiliary degree of freedom of the particle to clock the dwell time inside the barrier. We report on precise Larmor time measurements of ultracold ${}^{87}\mathrm{Rb}$ atoms tunneling through an optical barrier, which confirm longstanding predictions of tunneling times. We observe that atoms generally spend less time tunneling through higher barriers and that this time decreases for lower energy particles. For the lowest measured incident energy, at least 90% of transmitted atoms tunneled through the barrier, spending an average of $0.59\pm 0.02\mathrm{ms}$ inside. This is $0.11\pm 0.03\mathrm{ms}$ faster than atoms traversing the same barrier with energy close to the barrier’s peak and $0.21\pm 0.03\mathrm{ms}$ faster than when the atoms traverse a barrier with 23% less energy.

中文翻译：

---

低入射能量下拉莫尔隧道掘进时间减少的观察

隧穿粒子在势垒中花费多少时间？拉莫钟是回答这个问题的一种建议，它使用粒子的辅助自由度来测量粒子与势垒区域之间的相互作用，以计时势垒内的停留时间。我们报告了超冷的精确拉莫尔时间测量${}^{87}铷$原子隧穿光势垒，这证实了长期以来对隧穿时间的预测。我们观察到，原子穿过更高势垒的时间通常更少，而对于低能量粒子，这个时间会减少。对于最低测量的入射能量，至少 90% 的透射原子穿过势垒，平均花费$0.59\pm 0.02\mathrm{多发性硬化症}$里面。这是$0.11\pm 0.03\mathrm{多发性硬化症}$ 比以接近势垒峰值的能量穿过相同势垒的原子更快，并且 $0.21\pm 0.03\mathrm{多发性硬化症}$ 比原子以少 23% 的能量穿过势垒时更快。