Towards Simultaneous Observation of Path and Interference of Single\n Photon in a Modified Mach-Zehnder Interferometer

Abstract

Classical wisdom of wave-particle duality says that it is impossible to\nobserve simultaneously the wave and particle nature of microscopic object.\nMathematically the principle requests that the interference visibility V and\nwhich-path distinguishability D satisfy an orthodox limit of\nsquare(V)+square(D)<=1. This work presents a new wave-particle duality test\nexperiment with single photon in a modified Mach-Zehnder interferometer and\nconvincingly show the possibility of breaking the limit. The key element of the\ninterferometer is a weakly-scattering total-internal reflection prism surface,\nwhich exhibits pronounced single-photon interference with a visibility up to\n0.97 and simultaneously provides path distinguishability of 0.83. Apparently\nsquare(V)+square(D)=1.63 far exceeds the orthodox limit set by the principle of\nwave-particle duality for single photon. It is expected that more delicate\nexperiments in future should be able to demonstrate the ultimate regime of\nsquare(V)+square(D) approaching 2 and shed new light on the foundations of\ncontemporary quantum mechanics.\n