Photon Characteristics on a Beam Splitter for Copenhagen Interpretation

Abstract

The core of quantum information technology is based on quantum entanglement. Quantum entanglement is based on the laws of quantum physics based on the principle of uncertainty and coherence, where quantum entanglement has been used for various quantum information focusing on the mysterious phenomena not found in classical physics. Quantum entanglement emerged in 1935 by the EPR paradox, where the hidden variable leads to contradictions to quantum physics of Bell inequality. In the HBT experiments conducted in 1956, intensity correlation via a single beam splitter for stellar lights opened a new realm of quantum mechanics based on the particle nature of a photon compared with amplitude correlation in classical coherence optics. After that, bipartite photon correlation via a spontaneous parametric down conversion (SPDC) process was developed, and a nonclassical feature of anticorrelation, the so-called Hong-Ou-Mandel (HOM) dip was observed, where the anticorrelation cannot be achieved by classical physics. In addition, the SPDC-generated entangled photons were used for self-interference in a Mach-Zehnder interferometer (MZI), proving path superposition of a single photon in measurements. According to Copenhagen interpretation of quantum mechanics, a photon can be viewed as either a particle or a wave, but not both ways simultaneously. This mutual exclusion principle of a photon results in the wave-particle duality or complementarity theory. In the present thesis, anticorrelation proposed in ref. 32 was experimentally demonstrated using nearly sub-Poisson distributed coherent photons from an attenuated HeNe laser. The present thesis is to support the wave nature of photons in an interferometric system rather than the particle nature of photons for quantum correlation, leading to deterministic quantum features.