标题： 空间多模参量下转换在空间非相干光泵浦下的局域实在论的违背 显示英文标题

标题： Violation of local realism with spatially multimode parametric down-conversion pumped by spatially incoherent light

摘要： 我们实验上展示了对由空间非相干光源——发光二极管（LED）泵浦的自发参量下转换（SPDC）产生的偏振纠缠双光子态的局部实在论的违背，且空间后选择的影响可以忽略不计。 虽然现有研究仅通过将LED泵浦的SPDC后选择到单一空间探测模式来观察这种违背，但我们使用一个支持超过45,000个空间模式的多模探测装置，实现了$S = 2.532 \pm 0.069 > 2$的 Clauser-Horne-Shimony-Holt 不等式违背。 这些结果表明，用于SPDC的纠缠生成不需要相干泵浦源，如激光器。 我们的工作可能为量子技术提供新颖且实用的纠缠光子源，例如设备无关的量子密钥分发和量子增强传感。 显示英文摘要

摘要： We experimentally demonstrate a violation of local realism with negligible spatial postselection on the polarization-entangled two-photon states produced by spontaneous parametric down-conversion (SPDC) pumped by a spatially incoherent light source-a light-emitting diode (LED). While existing studies have observed such a violation only by post-selecting the LED-pumped SPDC into a single spatial detection mode, we achieve a Clauser-Horne-Shimony-Holt inequality violation of $S = 2.532 \pm 0.069 > 2$ using a spatially multimode detection setup that supports more than 45,000 spatial modes. These results indicate that coherent pump sources, such as lasers, are not required for SPDC-based entanglement generation. Our work could enable novel and practical sources of entangled photons for quantum technologies such as device-independent quantum key distribution and quantum-enhanced sensing.