百年光子——纪念爱因斯坦“光量子论”诞生110 周年

1905年爱因斯坦首次提出“光量子”概念，不仅宣告量子光学诞生，而且对其后量子物理发展产生重大推动作用。一百多年来，人类逐渐领略了光子的魅力，并且开始在量子密码、量子网络、量子模拟、量子计量和量子计算等领域展开了光子的应用。但时至今日，光子究竟是什么这一问题仍然是个谜。

A hundred years of the photon

In 1905 Albert Einstein developed the theory of the photoelectric effect. That was the beginning of quantum optics, and it helped to initiate quantum physics. For over 100 years, people have gradually come to appreciate the allure of photons, and to exploit its applications in quantum cryptography, quantum networks, quantum simulation, quantum metrology and quantum computing. But even today the nature of the photon is still an outstanding issue.