Editing Faster-than-light (section)

====EPR paradox====
{{Main|EPR paradox}}

The EPR paradox refers to a famous [[thought experiment]] of [[Albert Einstein]], [[Boris Podolsky]] and [[Nathan Rosen]] that was realized experimentally for the first time by [[Alain Aspect]] in 1981 and 1982 in the [[Aspect experiment]]. In this experiment, the two measurements of an [[quantum entanglement|entangled]] state are correlated even when the measurements are distant from the source and each other. However, no information can be transmitted this way; the answer to whether or not the measurement actually affects the other quantum system comes down to which [[interpretations of quantum mechanics|interpretation of quantum mechanics]] one subscribes to.

An experiment performed in 1997 by [[Nicolas Gisin]] has demonstrated quantum correlations between particles separated by over 10 kilometers.<ref>
{{cite web
|last=Suarez |first=A.
|date=26 February 2015
|title=History
|url=http://www.quantumphil.org/history.htm
|publisher=Center for Quantum Philosophy
|access-date=2017-06-07
}}</ref> But as noted earlier, the non-local correlations seen in entanglement cannot actually be used to transmit classical information faster than light, so that relativistic causality is preserved. The situation is akin to sharing a synchronized coin flip, where the second person to flip their coin will always see the opposite of what the first person sees, but neither has any way of knowing whether they were the first or second flipper, without communicating classically. See [[No-communication theorem]] for further information. A 2008 quantum physics experiment also performed by Nicolas Gisin and his colleagues has determined that in any hypothetical [[hidden-variable theory#Non-local hidden-variable theory|non-local hidden-variable theory]], the speed of the [[quantum non-local connection]] (what Einstein called "spooky action at a distance") is at least 10,000 times the speed of light.<ref>
{{cite journal
|last1=Salart |first1=D.
|last2=Baas |first2=A.
|last3=Branciard |first3=C.
|last4=Gisin |first4=N.
|last5=Zbinden |first5=H.
|year=2008
|title=Testing spooky action at a distance
|journal=[[Nature (journal)|Nature]]
|volume=454 |issue=7206 |pages=861–864
|arxiv=0808.3316
|bibcode=2008Natur.454..861S
|doi=10.1038/nature07121
|pmid=18704081
|s2cid=4401216
}}</ref>