Second-Order Duality of Light and its Nonclassical Complementarity
Rikizo Ikuta · 2023
A single photon exhibits wave-particle duality in the Young's double-slit interferometer. The duality character-ized by an interference visibility$V$as the wave-like property and a which-path information$D$as the particle-like property has tradeoff relation$D^{2}+V^{2}\leq 1$known as complementarity [1]–[3]. There are a lot of studies about the complementary nature of photons from various viewpoints such as delayed-choice experiments, theoretical works related to the uncertainty principle, and so on. More recently, studies have expanded the concept of the wave-particle duality to higher-order interferometric scenarios, in which the input light includes two or more pho-tons [4], [5]. Despite having a long history, all previous studies have been related to phase correlation of optical states, which reason would be why the main focus in the first place is the investigation of the mysterious quantum nature of a photon, including the superposition principle.