Editing Quantum entanglement (section)

===Bell tests===
{{main|Bell test}}
A [[Bell test]], also known as ''Bell inequality test'' or ''Bell experiment'', is a real-world physics experiment designed to test the theory of quantum mechanics against the hypothesis of local hidden variables. These tests empirically evaluate the implications of [[Bell's theorem]]. To date, all Bell tests have found that the hypothesis of local hidden variables is inconsistent with the way that physical systems behave. Many types of Bell tests have been performed in physics laboratories, often with the goal of ameliorating problems of experimental design or set-up that could in principle affect the validity of the findings of earlier Bell tests. This is known as "closing loopholes in Bell tests".  In earlier tests, it could not be ruled out that the result at one point could have been subtly transmitted to the remote point, affecting the outcome at the second location.<ref name=":2">{{cite web |last=Francis |first=Matthew |date=30 October 2012 |title=Quantum entanglement shows that reality can't be local |url=https://arstechnica.com/science/2012/10/quantum-entanglement-shows-that-reality-cant-be-local/ |access-date=22 August 2023 |website=Ars Technica |language=en-us}}</ref> However, so-called "loophole-free" Bell tests have since been performed where the locations were sufficiently separated that communications at the speed of light would have taken longer—in one case, 10,000 times longer—than the interval between the measurements.<ref name=":1">{{cite journal |last1=Matson |first1=John |title=Quantum teleportation achieved over record distances |journal=Nature News |date=13 August 2012 |doi=10.1038/nature.2012.11163 |s2cid=124852641}}</ref><ref name=":0">
{{cite journal 
 |title =Bounding the speed of 'spooky action at a distance 
 |journal =Physical Review Letters |volume=110 |issue =26 |page=260407 |year =2013
 |arxiv =1303.0614
 |bibcode =2013PhRvL.110z0407Y
 |doi = 10.1103/PhysRevLett.110.260407
 |pmid =23848853
 |last1 =Yin |first1 =Juan |last2 =Cao |first2 =Yuan |last3 =Yong |first3 =Hai-Lin |last4 =Ren |first4 =Ji-Gang
 |last5 =Liang |first5 =Hao |last6 =Liao |first6 =Sheng-Kai |last7 =Zhou |first7 =Fei |last8 =Liu |first8 =Chang
 |last9 =Wu |first9 =Yu-Ping |last10 =Pan |first10 =Ge-Sheng |last11 =Li |first11 =Li |last12 =Liu |first12 =Nai-Le
 |last13 =Zhang |first13 =Qiang |last14 =Peng |first14 =Cheng-Zhi |last15 =Pan |first15 =Jian-Wei
 |display-authors=4
 |s2cid =119293698
}}</ref><ref name="NTR-20151021"/><ref name="hanson"/>

In 2017, Yin et al. reported setting a new quantum entanglement distance record of 1,203&nbsp;km, demonstrating the survival of a two-photon pair and a violation of a Bell inequality, reaching a [[CHSH inequality|CHSH valuation]] of {{val|2.37|0.09}}, under strict Einstein locality conditions, from the [[Quantum Experiments at Space Scale|Micius satellite]] to bases in Lijian, Yunnan and Delingha, Qinghai, increasing the efficiency of transmission over prior fiberoptic experiments by an order of magnitude.<ref>{{cite journal | doi = 10.1126/science.aan3211 | volume=356 | title=Satellite-based entanglement distribution over 1200 kilometers | year=2017 | journal=Science | pages=1140–1144 | last1 = Yin | first1 = Juan | last2 = Cao | first2 = Yuan | last3 = Li | first3 = Yu-Huai | last4 = Liao | first4 = Sheng-Kai | last5 = Zhang | first5 = Liang | last6 = Ren | first6 = Ji-Gang | last7 = Cai | first7 = Wen-Qi | last8 = Liu | first8 = Wei-Yue | last9 = Li | first9 = Bo | last10 = Dai | first10 = Hui | last11 = Li | first11 = Guang-Bing | last12 = Lu | first12 = Qi-Ming | last13 = Gong | first13 = Yun-Hong | last14 = Xu | first14 = Yu | last15 = Li | first15 = Shuang-Lin | last16 = Li | first16 = Feng-Zhi | last17 = Yin | first17 = Ya-Yun | last18 = Jiang | first18 = Zi-Qing | last19 = Li | first19 = Ming | last20 = Jia | first20 = Jian-Jun | last21 = Ren | first21 = Ge | last22 = He | first22 = Dong | last23 = Zhou | first23 = Yi-Lin | last24 = Zhang | first24 = Xiao-Xiang | last25 = Wang | first25 = Na | last26 = Chang | first26 = Xiang | last27 = Zhu | first27 = Zhen-Cai | last28 = Liu | first28 = Nai-Le | last29 = Chen | first29 = Yu-Ao | last30 = Lu | first30 = Chao-Yang | last31 = Shu | first31 = Rong | last32 = Peng | first32 = Cheng-Zhi | last33 = Wang | first33 = Jian-Yu | last34 = Pan | first34 = Jian-Wei | issue=6343 | pmid = 28619937| arxiv=1707.01339 | doi-access = free |display-authors=4 }}</ref><ref>{{cite news | work=[[Science (journal)|Science]] |first=Gabriel |last=Popkin |url=https://www.science.org/content/article/china-s-quantum-satellite-achieves-spooky-action-record-distance | title=China's quantum satellite achieves 'spooky action' at record distance| date=14 June 2017}}</ref>