Editing No-communication theorem (section)

== History==
In 1978, Phillippe H. Eberhard's paper, ''Bell's Theorem and the Different Concepts of Locality'', rigorously demonstrated the impossibility of faster-than-light communication through quantum systems.<ref>{{Cite journal |last=Eberhard |first=P. H. |date=1978-08-01 |title=Bell's theorem and the different concepts of locality |url=https://link.springer.com/article/10.1007/BF02728628 |journal=Il Nuovo Cimento B (1971-1996) |language=en |volume=46 |issue=2 |pages=392–419 |doi=10.1007/BF02728628 |bibcode=1978NCimB..46..392E |issn=1826-9877}}</ref> Eberhard introduced several mathematical concepts of locality and showed how quantum mechanics contradicts most of them while preserving causality.

Further, in 1988, the paper ''Quantum Field Theory Cannot Provide Faster-Than-Light Communication'' by Eberhard and Ronald R. Ross analyzed how relativistic quantum field theory inherently forbids faster-than-light communication.<ref>{{Cite journal |last1=Eberhard |first1=Phillippe H. |last2=Ross |first2=Ronald R. |date=1989-03-01 |title=Quantum field theory cannot provide faster-than-light communication |url=https://link.springer.com/article/10.1007/BF00696109 |journal=Foundations of Physics Letters |language=en |volume=2 |issue=2 |pages=127–149 |doi=10.1007/BF00696109 |bibcode=1989FoPhL...2..127E |issn=1572-9524}}</ref> This work elaborates on how misinterpretations of quantum field properties had led to claims of superluminal communication and pinpoints the mathematical principles that prevent it.

In regards to communication, a quantum channel can always be used to transfer classical information by means of shared quantum states.<ref>Quantum Information, Computation and cryptography, Benatti, Fannes, Floreanini, Petritis: pp 210 - theorem HSV and Lemma 1</ref><ref>Lajos Diósi, A Short Course in Quantum Information Theory - An Approach From Theoretical Physics 2006 Ch 10. pp 87</ref> 
In 2008 [[Matthew Hastings]] proved a counterexample where the minimum output entropy is not additive for all quantum channels. Therefore, by an equivalence result due to [[Peter Shor]],<ref>{{cite journal |last1=Shor |first1=Peter W. |title=Equivalence of Additivity Questions in Quantum Information Theory |journal=Communications in Mathematical Physics |date=1 April 2004 |volume=246 |issue=3 |pages=453–472 |doi=10.1007/s00220-003-0981-7 |arxiv=quant-ph/0305035 |bibcode=2004CMaPh.246..453S |s2cid=189829228 }}</ref> the Holevo capacity is not just additive, but super-additive like the entropy, and by consequence there may be some quantum channels where you can transfer more than the classical capacity.<ref>{{cite journal |last1=Hastings |first1=M. B. |title=Superadditivity of communication capacity using entangled inputs |journal=Nature Physics |date=April 2009 |volume=5 |issue=4 |pages=255–257 |doi=10.1038/nphys1224 |arxiv=0809.3972 |bibcode=2009NatPh...5..255H |s2cid=199687264 }}</ref><ref>Quantum Information, Computation and cryptography, Benatti, Fannes, Floreanini, Petritis: pp 212</ref> Typically overall communication happens at the same time via quantum and non quantum channels, and in general time ordering and causality cannot be violated.

In August 24, 2015, a team led by physicist Ronald Hanson from Delft University of Technology in the Netherlands uploaded their latest paper to the preprint website arXiv, reporting the first Bell experiment that simultaneously addressed both the detection loophole and the communication loophole. The research team used a clever technique known as "entanglement swapping," which combines the benefits of photons and matter particles. The final measurements showed coherence between the two electrons that exceeded the Bell limit, once again supporting the standard view of quantum mechanics and rejecting Einstein's hidden variable theory. Furthermore, since electrons are easily detectable, the detection loophole is no longer an issue, and the large distance between the two electrons also eliminates the communication loophole.<ref name=":0">{{Citation |last1=Hensen |first1=B. |title=Loophole-free Bell inequality violation using electron spins separated by 1.3 kilometres |date=2015-08-24 |arxiv=1508.05949 |last2=Bernien |first2=H. |last3=Dréau |first3=A. E. |last4=Reiserer |first4=A. |last5=Kalb |first5=N. |last6=Blok |first6=M. S. |last7=Ruitenberg |first7=J. |last8=Vermeulen |first8=R. F. L. |last9=Schouten |first9=R. N.|journal=Nature |volume=526 |issue=7575 |pages=682–686 |doi=10.1038/nature15759 |pmid=26503041 |bibcode=2015Natur.526..682H }}</ref>