The output randomness from a random number generator can be certified by observing the violation of quantum contextuality inequalities based on the Kochen-Specker theorem. Contextuality can be tested in a single quantum system, which significantly simplifies the experimental requirements to observe the violation comparing to the ones based on nonlocality tests. However, it is not yet resolved as to how to ensure compatibilities for sequential measurements that is required in contextuality tests. Here, we employ a modified Klyachko-Can-Binicioğlu-Shumovsky contextuality inequality, which can ease the strict compatibility requirement on measurements. On a trapped single ${}^{138}{\mathrm{Ba}}^{+}$ ion system, we experimentally demonstrate violation of the contextuality inequality and realize quantum random number expansion by closing detection loopholes. We perform $1.29\times {10}^8$ trials of experiments and extract a randomness of $5.28\times {10}^5$ bits with a speed of $270\mathrm{bits}{\mathrm{s}}^{-1}$. Our demonstration paves the way for practical high-speed spot-checking quantum random number expansion and other secure information processing applications.

中文翻译：

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量子语境确保随机性扩展

可以通过观察基于Kochen-Specker定理的量子上下文不等式的违反来证明随机数发生器的输出随机性。上下文可以在单个量子系统中进行测试，与基于非本地性测试的违规行为相比，可以显着简化观察违规行为的实验要求。但是，关于如何确保上下文测试所需的顺序测量的兼容性，目前尚无定论。在这里，我们采用了经过修改的Klyachko-Can-Binicioğlu-Shumovsky上下文不等式，它可以缓解对测量的严格兼容性要求。在被困的单身${}^{138}{巴}^{+}$离子系统，我们通过实验证明违反了上下文不等式，并通过关闭检测漏洞实现了量子随机数扩展。我们执行$1.29\times {10}^8$ 试验并提取随机性 $5.28\times {10}^5$ 速度为 $270位{\mathrm{s}}^{-\mathrm{1个}}$。我们的演示为实际的高速抽查量子随机数扩展和其他安全信息处理应用铺平了道路。