Assuring quantum randomness from simple optical measurements

随机数是科学和技术的基本部分，与密码学、游戏、模拟或统计特别相关。量子随机数发生器(QRNG)依靠量子力学的内在随机性来产生真实且不可预测的随机数，这在经典物理学的角度是无法实现的。验证和量化量子系统输出的随机性的方法和协议是当前深入研究的主题。在本论文中，我们针对量子随机数产生的涌现领域，提出了两种半服务无关的量子熵获取方案，并详细讨论了这两种方案的优缺点。为了制定这些方法的认证协议，我们彻底研究了光电探测器的实现以及它可能在我们的方法中引入的漏洞。最后，我们进行了一个概念验证实验来证明所提出的方案的可行性，并通过实验研究了所得到的理论模型的正确性。这些实验的结果显示出与理论的令人满意的一致性，并且使我们能够通过8位的数字化从我们的QRNG中提取出每个样本1.58位的量子随机性。

Random numbers are a fundamental part of science and technology, being especially relevant forcryptography, gaming, simulations or statistics. Quantum random number generators (QRNG) rely onthe intrinsic randomness of quantum mechanics to generate true and unpredictable random numbers,unachievable from the classical physics perspective. Methods and protocols to certify and quantifythe randomness in the output of a quantum system are a current subject of intensive research. Inthis thesis, we focus on the emergent field of quantum random number generation proposing two semidevice-independent schemes to harvest quantum entropy while discussing in detail their strengths andweaknesses. With the purpose of developing a certification protocol for these approaches, we thoroughlystudy the implementation of the photodetector and the possible vulnerabilities it might introduce inour approaches. Finally, we perform a proof-of-concept experiment to demonstrate the feasibility ofthe suggested schemes and experimentally investigate the correctness of the derived theoretical models.The results for these experiments revealed a satisfactory agreement with the theory and enabled us toextract 1.58 bits of quantum randomness per sample with an 8-bit digitisation out of our QRNG.