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quantum entanglement

n. (context physics English) a quantum mechanical phenomenon in which the quantum states of two or more objects have to be described with reference to each other, even though the individual objects are spatially separated

Wikipedia
Quantum entanglement

Quantum entanglement is a physical phenomenon that occurs when pairs or groups of particles are generated or interact in ways such that the quantum state of each particle cannot be described independently of the others, even when the particles are separated by a large distance — instead, a quantum state must be described for the system as a whole.

Measurements of physical properties such as position, momentum, spin, polarization, etc., performed on entangled particles are found to be appropriately correlated. For example, if a pair of particles are generated in such a way that their total spin is known to be zero, and one particle is found to have clockwise spin on a certain axis, then the spin of the other particle, measured on the same axis, will be found to be counterclockwise, as to be expected due to their entanglement. However, this behavior gives rise to paradoxical effects: any measurement of a property of a particle can be seen as acting on that particle (e.g., by collapsing a number of superposed states) and will change the original quantum property by some unknown amount; and in the case of entangled particles, such a measurement will be on the entangled system as a whole. It thus appears that one particle of an entangled pair "knows" what measurement has been performed on the other, and with what outcome, even though there is no known means for such information to be communicated between the particles, which at the time of measurement may be separated by arbitrarily large distances.

Such phenomena were the subject of a 1935 paper by Albert Einstein, Boris Podolsky, and Nathan Rosen, and several papers by Erwin Schrödinger shortly thereafter, describing what came to be known as the EPR paradox. Einstein and others considered such behavior to be impossible, as it violated the local realist view of causality (Einstein referring to it as "spooky action at a distance") and argued that the accepted formulation of quantum mechanics must therefore be incomplete. Later, however, the counterintuitive predictions of quantum mechanics were verified experimentally. Experiments have been performed involving measuring the polarization or spin of entangled particles in different directions, which — by producing violations of Bell's inequality — demonstrate statistically that the local realist view cannot be correct. This has been shown to occur even when the measurements are performed more quickly than light could travel between the sites of measurement: there is no lightspeed or slower influence that can pass between the entangled particles.Francis, Matthew.

Quantum entanglement shows that reality can't be local, Ars Technica, 30 October 2012 Recent experiments have measured entangled particles within less than one hundredth of a percent of the travel time of light between them. According to the formalism of quantum theory, the effect of measurement happens instantly. It is not possible, however, to use this effect to transmit classical information at faster-than-light speeds (see Faster-than-light § Quantum mechanics).

Quantum entanglement is an area of extremely active research by the physics community, and its effects have been demonstrated experimentally with photons, neutrinos, electrons, molecules the size of buckyballs, and even small diamonds. Research is also focused on the utilization of entanglement effects in communication and computation.

Usage examples of "quantum entanglement".

Move the entangled quantum dots apart via FTL and you break the quantum entanglement they rely on.

There has been no response from the router, the strange alien artifact in orbit around the brown dwarf, since the crew of the starwhisp uploaded themselves through its strange quantum entanglement interface for transmission to whatever alien network it connects to.

Since the Quantum Entanglement Energy link is the only signal they're receiving, they probably assume it's coming from our ship, and furthermore that the Vines are operating the ship.

Quantum physics was akin to alchemy in my mindalchemy that workedand to push ahead without someone qualified to handle problems like quantum entanglement and unwanted tunneling would be madness.

You mean like the quantum entanglement radios the astronauts are using on Europa to communicate instantly with Earth.

It is not clear how far this technique can be advanced, or what practical limits there may be on quantum entanglement (coupled states tend to decouple from each other, because of their interactions with the rest of the universe).