Quantum correlation is the keyword in quantum information technologies. Over the last several decades, quantum correlation violating local realism has been intensively studied in various areas, but still left as a mysterious quantum phenomenon. Here, a coherence approach is applied to investigate the fundamental physics of nonlocal quantum correlation for a typical model based on entangled photon pairs without violation of quantum mechanics. As a result, a complete coherence solutions are found for coherent photons via coincidence detection, resulting in a deterministic joint basis relation between space-like separated parties in an inseparable basis-product manner.
Quantum correlation is the keyword in quantum information technologies. Over the last several decades, quantum correlation violating local realism has been intensively studied in various areas, but still left as a mysterious quantum phenomenon. Here, a coherence approach is applied to investigate the fundamental physics of nonlocal quantum correlation for a typical model based on entangled photon pairs without violation of quantum mechanics. As a result, a complete coherence solutions are found for coherent photons via coincidence detection, resulting in a deterministic joint basis relation between space-like separated parties in an inseparable basis-product manner.
Entanglement is the basic building block of quantum technologies whose property is in the unique quantum feature of nonlocal realism. However, such a nonlocal quantum property is known as just a weird phenomenon that cannot be obtained by any classical means. Recently, the mysterious quantum phenomena have been coherently interpreted using entangled photon pairs, where the quantum mystery has been found in the manipulated product-basis superposition of paired photons. Here, a coherence version of the Franson-type nonlocal correlation is presented by all means of classical physics. The resulting coherence solutions of the nonlocal correlation satisfy the same joint-phase relation of local parameters as in the quantum version. For the nonlocal correlation fringe, coherent manipulations of attenuated laser light are conducted by synchronized acousto-optic modulators to generate random but phase-matched photon pairs.
Abstract Bell inequality violation is a quantitative measurement tool of quantum entanglement between space-like separated particles. Quantum entanglement is the heart of quantum information science, in which the resulting nonlocal correlation between the paired particles is a unique property of quantum mechanics. Over the last few decades, intensive research has been conducted to understand nonlocal quantum features based on the particle nature of quantum mechanics. Here, the role of coincidence detection is analyzed in a simple interferometer using a quantum eraser. To understand the nonlocal quantum feature, coincidence detection between two output photons of an interferometer is coherently analyzed for Bell inequality violations. Based on this understanding, a classical model of the nonlocal quantum correlation is finally presented using coherent light via wave mixing and heterodyne detection.
Bell inequality violation is a quantitative measurement tool for quantum entanglement. Quantum entanglement is the heart of quantum information science, in which the resulting nonlocal correlation between remotely separated photons shows a unique property of quantum mechanics. Here, the role of coincidence detection is coherently investigated for the nonlocal correlation in a simple polarization-basis selective non-interferometric system using entangled photon pairs (Phys. Rev. A 73, 012316 (2006)). The resulting nonlocal quantum feature between two independent local polarizers is coherently derived for the joint-parameter relation of the inseparable intensity product. The resulting coherence solution based on the wave nature of quantum mechanics is thus understood as a deterministic process via coincidence detection-caused measurement modification.
Quantum technologies based on the particle nature of a photon has been progressed over the last several decades, where the fundamental quantum features of entanglement have been tested by Hong-Ou-Mandel-type anticorrelation and Bell-type nonlocal correlation. Recently, mutually exclusive quantum features based on the wave nature of a photon have been investigated to understand the fundamental physics of mysterious quantum correlation, resulting in deterministic and macroscopic quantum technologies. Here, we study the quantum natures of paired photons acting on a beam splitter, where mutual coherence plays a major role. Unlike current common understanding on anticorrelation, bipartite entanglement between paired photons does not have to be probabilistic or post-selected, but can be deterministic and even macroscopic via phase basis manipulation without violating quantum mechanics.
Coincidence detection is a key technique used in nonlocal quantum-correlation measurements to test Bell inequality violation between remotely separated local detectors. With individual uniform intensity of local measurements, the nonlocal correlation fringe is a mysterious quantum feature that cannot be achieved classically. Here, the coincidence detection is coherently investigated to understand the fundamental physics of the nonlocal correlation fringe via second-order quantum superposition between selected nonlocal measurement events. Because of the coherence feature of paired photons, the coincidence technique modifies the measurement events for the rule of thumb of indistinguishability between selected measurement bases of paired photons. This indistinguishability is quantum superposition between nonlocally detected events resulting from a selected time slot of coincidence, where coherence between individually measured photons is an absolute condition.
Quantum entanglement, a quintessential feature of quantum mechanics, has profound implications on our understanding of the fundamental nature of reality. This phenomenon, in which quantum particles exhibit correlations that defy classical intuition, has captivated physicists and philosophers alike. The existence of nonlocal correlations, a hallmark of entanglement, challenges the principles of local realism and calls into question our notions of causality and locality. This paper explores the theoretical foundations, experimental evidence, and interpretations surrounding quantum entanglement and nonlocal correlations. It delves into the historical context, highlighting the pioneering work of physicists such as Einstein, Podolsky, Rosen, and Bell, whose contributions paved the way for our current understanding of this enigmatic concept. The paper also examines the potential applications of entanglement in fields such as quantum computing, cryptography, and communication, underscoring its technological significance. Furthermore, it discusses the philosophical implications of nonlocal correlations, shedding light on the ongoing debates surrounding the interpretation of quantum mechanics and the nature of reality itself. Keywords: Quantum entanglement, Nonlocal correlations, Local realism, Causality, Locality, Quantum mechanics, Experimental evidence, Theoretical foundations, Einstein-Podolsky-Rosen (EPR) paradox, Bell's theorem, Quantum computing.