Spin noise based quantum random number generators first appeared in 2008 and have since then garnered little further interest, in part because their bit rate is limited by the transverse relaxation time $T_{2}$ which for coated alkali vapour cells is typically in the kbit/s range. Here we present two advances. The first is an improved bit generation protocol that allows generating bits at rates exceeding $1/T_{2}$ with only a minor increase of serial correlations. The second is a significant reduction of the time $T_{2}$ itself by removing the coating, increasing the vapour temperature and introducing a magnetic-field gradient. In this way we managed to increase the bit generation rate to 1.04 Mbit/s. We analyse the quality of the generated random bits using entropy estimation and we discuss the extraction methods to obtain high-entropy bitstreams. We accurately predict the entropy output of the device backed with a stochastic model and numerical simulations.

中文翻译：

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Mbit/s 范围碱蒸气自旋噪声量子随机数发生器

基于自旋噪声的量子随机数发生器首次出现于 2008 年，此后就很少引起人们的兴趣，部分原因是它们的比特率受到横向弛豫时间 $T_{2}$ 的限制，对于涂层碱蒸气电池来说，横向弛豫时间通常为 kbit /s 范围。在这里，我们提出了两项​​进展。第一个是改进的位生成协议，允许以超过 $1/T_{2}$ 的速率生成位，而串行相关性仅略有增加。第二个是通过去除涂层、提高蒸汽温度和引入磁场梯度来显着缩短时间 $T_{2}$ 本身。通过这种方式，我们成功地将比特生成率提高到 1.04 Mbit/s。我们使用熵估计分析生成的随机比特的质量，并讨论获得高熵比特流的提取方法。我们通过随机模型和数值模拟准确预测设备的熵输出。