2021年12月09日 17:00 -- 12月09日 18:00
The main challenge for scaling up photonic quantum technologies is the lack of perfect quantum light sources. We have pushed the parametric down-conversion to its physical limit and produce two-photon source with simultaneously a collection efficiency of 97% and an indistinguishability of 96% between independent photons. Using a single quantum dot in microcavities, we have produced on-demand single photons with high purity (>99%), near-unity indistinguishability, and high extraction efficiency—all combined in a single device compatibly and simultaneously. Based on the high-performance quantum light sources, we have implemented boson sampling—which is an intermediate model of quantum computing, a strong candidate for demonstrating quantum computational advantage and refuting Extended Church Turing Thesis—with up to 76 photon clicks after a 100-mode interferometer. The photonic quantum computer, Jiuzhang, yields an output state space dimension of 10^30 and a sampling rate that is 10^14 faster using the state-of-the-art simulation strategy on supercomputers.报告人:陆朝阳,1982年12月出生于浙江,剑桥大学物理学博士,中国科学技术大学教授。陆朝阳长期致力于面向实用化的量子信息技术研究,在包括《自然》和《科学》11篇、《自然》子刊12篇、《美国科学院院刊》5篇、《物理评论快报》48篇等国际顶级学术期刊发表论文100余篇,被引用15800余次。2020年,潘建伟、陆朝阳等研究团队成功构建了76个光子100个模式的高斯玻色取样量子计算原型机“九章”,输出量子态空间规模达到了10^30,处理高斯玻色取样的速度比超级计算机快一百万亿倍。这一成果使得我国成功达到了量子计算研究的第一个里程碑:量子计算优越性(国外也称之为“量子霸权”)。今年,他们又升级到了“九章二号”,达到了113个光子。“九章”先后入选了包括中国科技年度十大进展、联合国教科文组织评选的全球十大数字创新、Falling Wall Top Ten Breakthroughs of the Year、腾讯青少年科学小会和Science评选的年度科学突破榜首等一系列奖项。此次的报告中,陆朝阳教授将为我们介绍团队如何自主研发具备高效率、高全同性、极高亮度和大规模扩展能力的量子光源,并且分享“九章”的最新研究进展。