We report observations of Cross-Double-Slit Experiment and Which-Path-Cross-Double-Slit experiment. Cross-Double-Slit apparatus contains two double-slit, where first double-slit is perpendicular to second double-slit. The first double-slit and the second double-slit generate not only their own interference pattern perpendicular to each other, but also generate “Cross-interference-patterns”. When we do which-way experiment with one of two double-slit, say first double-slit, then its interference pattern disappeared, i.e., photons behave as particles; but the second double-slit’s interference pattern and the cross-interference-pattern still exist; which implies an significant phenomenon that in the same experiment, photons behave as both wave and particle, which is first time caught on film. Thus we suggest to re-study wave-particle duality, which is the basic mystery of quantum mechanics. We postulate that the particle nature of photons is intrinsic; while the wave-like of photons is manifest-behavior.
We have performed cross-double-slit experiment and delayed-choice-cross-double-slit experiment, denoted as extended double-slit experiments. The cross-double-slit experiments show that the cross-double-slit apparatus creates not only two interference patterns, but also four cross-interference-patterns, which are created by two double-slit. The delayed-choice-cross-double-slit experiments disclose new phenomena: (1) photons behave as both wave and particle in the same experiment simultaneously, which violate Bohr’s complementarity; (2) the cross-interference-pattern is created by one double-slit and one single-slit; (3) photons passing through the same slit behave as both wave and particle, referred it as the Wave-Particle-Paradox, which demands extensive study. We suggest to re-study wave-particle duality.
Young's double slit experiments representing the mystery of quantum mechanics have been descripted by wave theories. To study the mystery, the double slit experiments were extended to the cross-double slit experiments. A description should explain all the double slit and cross-double slit experiments consistently. To test the wave description, the two postulates are proposed, which state that before passing through the double slit and before landing on the detector, photons behave as particles, but not as waves. To test the two postulates, the comprehensive double slit/cross-double slit experiments are proposed and performed. By placing shields and/or blockers near the detector/screen, the comprehensive double slit/cross-double slit experiments show that the fringes are created independently and partially, which discloses the particle nature of photons in the double slit/crossdouble slit experiments and violates the wave descriptions. The comprehensive double slit/cross-double slit experiments provide the comprehensive phenomena for developing theoretical model to study the mystery of double slit, complementarity principle, wave-particle duality, and wave theory of light.