Ever since Schrödinger envisioned the possibility of quantum entanglement, in 1935, by contemplating the implications of the meaning of ‘not complete’ emitted by Einstein and colleagues towards quantum mechanics the word paradox has been brought forth. Paradox was again invoked by Bohm in the 1950s and of course the creation of Bell's theorem was motivated by it. Paradox has been a trademark of the philosophical path towards quantum entanglement. And yet, the physics tells us that quantum entanglement is not afflicted at all by any paradox whatsoever. That this was the case was first silently implied by the physics of Dirac, Wheeler, and Pryce and Ward (1930–1947) and directly articulated by Feynman in 1965. Here we transparently show that, from the quantum interference perspective, the physics of quantum entanglement is completely and utterly free of paradoxes.
Ever since Schrödinger envisioned the possibility of quantum entanglement, in 1935, by contemplating the implications of the meaning of ‘not complete’ emitted by Einstein and colleagues towards quantum mechanics the word paradox has been brought forth. Paradox was again invoked by Bohm in the 1950s and of course the creation of Bell's theorem was motivated by it. Paradox has been a trademark of the philosophical path towards quantum entanglement. And yet, the physics tells us that quantum entanglement is not afflicted at all by any paradox whatsoever. That this was the case was first silently implied by the physics of Dirac, Wheeler, and Pryce and Ward (1930–1947) and directly articulated by Feynman in 1965. Here we transparently show that, from the quantum interference perspective, the physics of quantum entanglement is completely and utterly free of paradoxes.
The experimental origin of quantum mechanics is highlighted, and essential features of the photon are described. The philosophical path to quantum entanglement, as defined by the works of EPR–Bohm and Aharonov–Bell, and the physics path to quantum entanglement, as defined by the works of Dirac–Wheeler–Pryce and Ward, are introduced and discussed. The probability amplitude for quantum Entanglement, discovered in 1947, is then introduced prior to a high-level overview of the field. This introduction then concludes with a chapter-by- chapter description of the book and its purpose.
The experimental origin of quantum mechanics is highlighted and essential features of the photon are described. The philosophical path to quantum entanglement, as defined by the works of EPR to Bohm and Aharonov to Bell, and the physics path to quantum entanglement, as defined by the works of Dirac to Wheeler to Pryce and Ward, are introduced and discussed. The probability amplitude for quantum entanglement, discovered in 1947, is then introduced prior to a high-level overview of the field. The introduction then concludes with a chapter-by-chapter description of this book and its aims.
Quantum interference and quantum entanglement are intrinsically ‘entangled’ at the most fundamental strata of quantum mechanics. In fact, John Clive Ward defined the whole of quantum mechanics in the following terms: ‘ the probability amplitude of quantum entanglement … was my first lesson in quantum mechanics, and in a very real sense my last, since all the rest is mere technique, which can be learnt from books. ’ Albeit Ward's opinion is somewhat colored by his ineffable genius, there is no doubt that quantum entanglement is at the foundations of quantum mechanics. Quantum entanglement encapsulates indeterminacy, superposition, and nonlocality with sublime cohesiveness. In this chapter we describe the fine details of the physics of quantum entanglement, free of paradoxes, its interferometric origin, and its generalized character.
How it all began In 1935, a decade after the invention of quantum theory by Heisenberg (1925) and Schrödinger (1926), three papers appeared, setting the stage for a new concept, quantum entanglement. The previous decade had already seen momentous discussions on the meaning of the new theory, for example by Niels Bohr (see his contribution to Albert Einstein: Philosopher-Scientist in Further reading); but these new papers opened up the gates for a new, very deep philosophical debate about the nature of reality, about the role of knowledge, and about their relation. Since the 1970s, it has become possible for experimenters to observe entanglement directly in the laboratory and thus test the counter-intuitive predictions of quantum mechanics whose confirmation today is beyond reasonable doubt. Since the 1990s, the conceptual and experimental developments have led to new concepts in information technology, including such topics as quantum cryptography, quantum teleportation, and quantum computation, in which entanglement plays a key role. In the first of the three papers, Einstein, Podolsky, and Rosen (EPR) realized that, if two particles had interacted in their past, their properties will remain connected in the future in a novel way, namely, observation on one determines the quantum state of the other, no matter how far away. Their conclusion was that quantum mechanics is incomplete and they expressed their belief that a more complete theory may be found. Niels Bohr replied that the two systems may never be considered independent of each other, and observation on one changes the possible predictions on the other. Finally, Erwin Schrödinger, in the paper which also proposed his famous cat paradox, coined the term “entanglement” (in German Verschränkung ) for the new situation and he called it “not one, but the essential trait of the new theory, the one which forces a complete departure from all classical concepts.”
This book presents quantum mechanics from two of its most fundamental pillars, quantum interference and quantum entanglement. It also explains how to arrive at iconic principles, in a clear and transparent manner. Quantum Clear: Quantum Mechanics Free of Paradoxes offers a refreshing perspective on quantum mechanics. Unlike conventional approaches, this book illuminates iconic principles such as Born's rule with remarkable clarity and transparency. What sets it apart from typical quantum science books is its deliberate avoidance of sensationalized vocabulary like 'mystery,' 'strange,' 'weird,' or 'paradox' that often clouds understanding. Instead, readers embark on a journey beginning with a comprehensive historical introduction to quantum mechanics and its major developments. The author methodically dismantles common misconceptions, including: Why the Einstein–Podolsky–Rosen (EPR) argument incorrectly labeled quantum mechanics as an 'incomplete' theory The philosophical and physical foundations of quantum entanglement Why the concept of 'wave function collapse' is unnecessary when properly observed from the physics of quantum interference and entanglement How the so-called 'measurement problem' dissolves when viewed through interferometric and entanglement perspectives The book then transitions to practical applications, explaining quantum communications, computing, cryptography, engineering, and teleportation in accessible language. Readers will glimpse the emerging world where quantum mechanical concepts become integrated into everyday engineering solutions. Though scientifically rigorous, Quantum Clear speaks to both scientific and general audiences, systematically unraveling the misunderstandings that have surrounded quantum mechanics for decades—offering clarity where confusion once reigned.