A coherence method generating macroscopic quantum features using polarization-basis control and its projection measurements of laser light

Abstract: Quantum entanglement between paired photons is the foundation of optical quantum computing, quantum sensing, and quantum networks. Traditionally, quantum information science has focused on the particle nature of photons at the microscopic scale, often neglecting the phase information of single photons, even for the bipartite quantum entanglement. Recently, a coherence-based approach has been explored to understand the so-called quantum mystery of nonlocal intensity fringes emerging from local randomness. Here, a pure coherence method is presented to create macroscopic quantum features using conventional laser light via linear optics-based measurement modifications. To achieve this, a polarization-basis control of the laser light is conducted to generate indistinguishable characteristics between orthogonally polarized light pairs. Using projection measurements of the polarization-controlled light pairs, we derive coherence solutions of local randomness and nonlocal correlations between independently controlled local parameters, where a fixed relative phase relationship between paired lights is an essential condition to determine the corresponding Bell states.