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On this level, of a sudden, all the rules of behavior, and we are familiar with, no longer held. Enter this strange new world very small, is a kind of experience, because inexplicably bizarre, because Alice's adventure park. In this fantasy world of quantum particles is the wave-wave particles. The slightest light, therefore, is the electromagnetic wave undulating through space, is a stream of tiny particles accelerated to observe, in a sense, or some experimental quantum phenomenon reveals the nature of waves, and some other particle, as well as with the nature of light, But never in these two areas at the same time. However, we observed that light, it is a wave is a stream of particles.           Quantum: The Realm of the Bizarre     Quantum mechanics is the strangest field in all of science. From our everyday perspective of life on Earth, nothing makes sense in quantum theory, the theory about the laws of nature that govern the realm of the very small (as well as some large systems, such as superconductors). The word itself, quantum, denotes a small packet of energy—a very small one. In quantum mechanics, as the quantum theory is called, we deal with the basic building blocks of matter, the constituent particles from which everything in the universe is made. These particles include atoms, molecules, neutrons, protons, electrons, quarks, as well as photon—the basic units of light. All these objects (if indeed they can be called objects) are much smaller than anything the human eye can see. At this level, suddenly, all the rules of behavior with which we are familiar no longer hold. Entering this strange new world of the very small is an experience as baffling and bizarre as Alice's adventures in Wonderland. In this unreal quantum world, particles are waves, and waves are particles. A ray of light, therefore, is both an electromagnetic wave undulating through space, and a stream of tiny particles speeding toward the observer, in the sense that some quantum experiments or phenomena reveal the wave nature of light, while others the particle nature of the same light—but never both aspects at the same time. And yet, before we observe a ray of light, it is both a wave and a stream of particles.   In the quantum realm everything is fuzzy—there is a hazy quality to all the entities we deal with, be they light or electrons or atoms or quarks. An uncertainty principle reigns in quantum mechanics, where most things cannot be seen or felt or known with precision, but only through a haze of probability and chance. Scientific predictions about the outcomes are statistical in nature and are given in terms of probabilities—we can only predict the most likely location of a particle, not its exact position. And we can never determine both a particle's location and its momentum with good accuracy. Furthermore, this fog that permeates the quantum world can never go away. There are no "hidden variables," which, if known, would increase our precision beyond the natural limit that rules the quantum world. The uncertainty, the fuzziness, the probabilities, the dispersion simply cannot go away—these mysterious, ambiguous, veiled elements are an integral part of this wonderland.   Even more inexplicable is the mysterious superposition of states of quantum systems. An electron (a negatively-charged elementary particle) or photon (a quantum of light) can be in a superposition of two or more states. No longer do we speak about "here or there;" in the quantum world we speak about "here and there." In a certain sense, a photon, part of a stream of light shone on a screen with two holes, can go through both holes at the same time, rather than the expected choice of one hole or the other. The electron in orbit around the nucleus is potentially at many locations at the same time.   But the most perplexing phenomenon in the bizarre world of the quantum is the effect called entanglement. Two particles that may be very far apart, even millions or billions of miles, are mysteriously linked together. Whatever happens to one of them immediately causes a change in the other one.   ...[W]e must let go of all our preconceptions about the world derived from our experience and our senses, and instead let mathematics lead the way.           — Amir D. Aczel, Entanglement: The Greatest Mystery in Physics                 Indexes/12