We demonstrate the interaction-induced blockade effect in an ultracold ${}^{88}2$ gas via studying the time dynamics of a two-photon excitation to the triplet Rydberg series $5sns{}^3{S}_1$ for five different principal quantum numbers $n$ ranging from 19 to 37. By using a multipulse excitation sequence to increase the detection sensitivity, we could identify Rydberg-excitation-induced atom losses as low as $<1\%$. Based on an optical Bloch equation formalism, treating the Rydberg-Rydberg interaction on a mean-field level, the van der Waals coefficients are extracted from the observed dynamics, which agree fairly well with ab initio calculations.

中文翻译：

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双光子激发动力学揭示的超冷锶气体中的里德堡阻塞

我们证明了在超冷条件下相互作用诱导的阻断效应 ${}^{88}2$ 通过研究对三重态里德堡级数的双光子激发的时间动力学 $5秒n秒{}^3{秒}_1$ 五个不同的主量子数 $n$ 范围从 19 到 37。通过使用多脉冲激发序列来提高检测灵敏度，我们可以识别里德堡激发引起的原子损失低至 $<1\%$. 基于光学布洛赫方程形式，在平均场水平上处理里德堡-里德堡相互作用，从观察到的动力学中提取范德华系数，这与ab initio计算非常吻合。