The phenomenon that Einstein thought too spooky and strange to be true
What is entanglement? It's a connection between quantum particles, the building blocks of the universe. Once two particles are entangled, a change to one of them is reflected---instantly---in the other, be they in the same lab or light-years apart. So counterintuitive is this phenomenon and its implications that Einstein himself called it "spooky" and thought that it would lead to the downfall of quantum theory. Yet scientists have since discovered that quantum entanglement, the "God Effect," was one of Einstein's few---and perhaps one of his greatest---mistakes.
What does it mean? The possibilities offered by a fuller understanding of the nature of entanglement read like something out of science fiction: communications devices that could span the stars, codes that cannot be broken, computers that dwarf today's machines in speed and power, teleportation, and more.
In The God Effect, veteran science writer Brian Clegg has written an exceptionally readable and fascinating (and equation-free) account of entanglement, its history, and its application. Fans of Brian Greene and Amir Aczel and those interested in the marvelous possibilities coming down the quantum road will find much to marvel, illuminate, and delight.
Science writer Clegg (A Brief History of Infinity), discussing the field of quantum mechanics, asserts that "very experiment takes us a step closer to realizing just how strange the world is at the quantum level." Quantum entanglement is the oddest of them all. As Clegg explains it, entanglement occurs when two particles (photons, atoms, electrons, etc.) become so intensely linked together that for all intents and purposes they become part of one unit. The mystifying thing is that this link continues even if the two particles are in different parts of the universe: "Make a change to one particle, and that change is instantly reflected in the other(s) however far apart they may be." Clegg does an excellent job of explaining this complex situation in nontechnical terms; he details the many experiments that have consistently suggested that entanglement is real. The implications for future technological advances are huge, and Clegg is at his finest as he embeds potential advances in a broad historical context. Data could be encrypted in unbreakable codes; computers could become thousands of times more powerful than today; objects, and maybe even living organisms, could be instantaneously transported. While highly speculative, these possibilities could change our notion of reality. 27 b&w illus.