Jim put a lot of energy here into replying to a joke. Jim appears to be an electronics supergenius.
On Mon, Jun 29, 2020, 4:48 AM jim bell <[email protected]> wrote: > Albert Einstein called it "spooky action at a distance". He hated the > concept of quantum mechanics, saying "God does not play dice with the > Universe". Unfortunately, Einstein was quite wrong. > > The idea is that pairs of photons can be generated and can go virtually > any distance, and then a measurement made on one of these photons > essentially instantaneously determines the equivalent value of the other > photon. There is apparently no limit to the distance over which this can > be done. A few years ago I read that the apparent velocity of this > connection is at least 10,000 times c, or the speed of light in a vacuum. > https://blogs.scientificamerican.com/news-blog/quantum-weirdnes-wins-again-entangl-2008-08-13/#:~:text=(In%202007%2C%20researchers%20transmitted%20entangled,two%20of%20the%20Canary%20Islands.)&text=But%20in%20reality%2C%20no%20experiment,times%20the%20speed%20of%20light. > > "The photons were indeed entangled, the group reports in *Nature* > <https://www.nature.com/nature/journal/v454/n7206/edsumm/e080814-10.html>. > But in reality, no experiment is perfect, so what they end up with is a > lower limit on how fast the entanglement could be traveling: 10,000 times > the speed of light." > > I'm not a good person to be explaining this to you: My degree is in > chemistry, not physics. > But read up on Bell's inequalities. (different Bell!) > https://en.wikipedia.org/wiki/Bell%27s_theorem > > > *"Bell's theorem* proves that quantum physics > <https://en.wikipedia.org/wiki/Quantum_physics> is incompatible with local > hidden variable theories > <https://en.wikipedia.org/wiki/Local_hidden_variable_theory>. It was > introduced by physicist John Stewart Bell > <https://en.wikipedia.org/wiki/John_Stewart_Bell> in a 1964 paper titled > "On the Einstein Podolsky Rosen Paradox > <https://en.wikipedia.org/wiki/EPR_paradox>", referring to a 1935 thought > experiment <https://en.wikipedia.org/wiki/Thought_experiment> that Albert > Einstein <https://en.wikipedia.org/wiki/Albert_Einstein>, Boris Podolsky > <https://en.wikipedia.org/wiki/Boris_Podolsky> and Nathan Rosen > <https://en.wikipedia.org/wiki/Nathan_Rosen> used to argue that quantum > physics is an "incomplete" theory.[1] > <https://en.wikipedia.org/wiki/Bell%27s_theorem#cite_note-EPR-1>[2] > <https://en.wikipedia.org/wiki/Bell%27s_theorem#cite_note-Bell1964-2> By > 1935, it was already recognized that the predictions of quantum physics are > probabilistic <https://en.wikipedia.org/wiki/Probability>. Einstein, > Podolsky and Rosen presented a scenario that, in their view, indicated that > quantum particles, like electrons <https://en.wikipedia.org/wiki/Electron> > and photons <https://en.wikipedia.org/wiki/Photon>, must carry physical > properties or attributes not included in quantum theory, and the > uncertainties in quantum theory's predictions are due to ignorance of these > properties, later termed "hidden variables". Their scenario involves a pair > of widely separated physical objects, prepared in such a way that the quantum > state <https://en.wikipedia.org/wiki/Quantum_state> of the pair is > entangled <https://en.wikipedia.org/wiki/Quantum_entanglement>. " > [partial quote] > > > Quantum communication over fiber optics has been done to a record distance > of 50 kilometers. > > > https://www.sciencedaily.com/releases/2019/08/190829150732.htm#:~:text=For%20the%20first%20time%2C%20a,for%20a%20future%20quantum%20internet.&text=FULL%20STORY-,For%20the%20first%20time%2C%20a%20team%20has%20sent%20a%20light,50%20km%20of%20optical%20fiber. > > > Ironically, I have actually made a major contribution to this field, > although almost nobody realizes it yet. The limit to the distance of > quantum entanglement, 50 kilometers above, is based on the amount of > optical loss present in the fiber. Prior to my invention, and currently, > the record for a low-loss single-mode optical fiber is by Sumitomo > Electric, and is 0.1419 db/kilometer. > https://global-sei.com/company/press/2017/03/prs029.html#:~:text=Now%20Sumitomo%20Electric%20has%20advanced,lowest%20loss%20of%20optical%20fiber. > > Fiber optics scientists and engineers achieved a fiber loss of about 0.200 > db/km in 1978, and about 0.160 by the mid-1980's. They are apparently > approaching a limit asymptotically, the limit defined by the presence of > natural-quantities of spin-containing isotopes in silica. > > In about December 2008, while stuck in a Federal prison cell at USP > Tucson, Arizona, I realized that the cause of the residual loss in these > fibers is the Si-29 and O-17 isotope atoms, and for Corning-type fibers > (containing germania, or GeO2, dopant), the Ge-73 isotope atoms. Remove > these spin-containing isotopes from optical fiber silica, and it should be > possible to drop the loss by at least a factor of 100, or to about > 0.001db/kilometer. > > (Corning-type fibers use a core of 8% GeO2 and 92% SiO2, and pure silica > in the cladding. Sumitomo-type fibers use(s) a pure-silica core, and a > fluorine-doped cladding. Since there are fewer spin-containing isotopes in > pure silica than in germania-doped silica, Sumitomo had/has a small loss > advantage over Corning.) > > If this fiber is used for comunication between New York and Ireland, the > hop should be achievable by a single, continuous fiber. It will not need > to contain the 40-odd EDFA > https://en.wikipedia.org/wiki/Optical_amplifier amplifiers currently > employed. > > Similarly, if such fiber is used for a quantum link, it should be possible > to do the link at least at a distance of 5000 kilometers, 100x better than > the recent (2019) record. > > The Chinese have been doing entanglement experiments on a satellite named > Micius. https://en.wikipedia.org/wiki/Quantum_Experiments_at_Space_Scale > > "QUESS is a proof-of-concept mission designed to facilitate quantum optics > <https://en.wikipedia.org/wiki/Quantum_optics> experiments over long > distances to allow the development of quantum encryption > <https://en.wikipedia.org/wiki/Quantum_encryption> and quantum > teleportation <https://en.wikipedia.org/wiki/Quantum_teleportation> > technology.[7] > <https://en.wikipedia.org/wiki/Quantum_Experiments_at_Space_Scale#cite_note-Spacecom-7> > Quantum > encryption uses the principle of entanglement > <https://en.wikipedia.org/wiki/Quantum_entanglement> to facilitate > communication that is totally safe against eavesdropping > <https://en.wikipedia.org/wiki/Eavesdropping>, let alone decryption > <https://en.wikipedia.org/wiki/Cryptanalysis>, by a third party. By > producing pairs of entangled photons > <https://en.wikipedia.org/wiki/Photons>, QUESS will allow ground stations > separated by many thousands of kilometres to establish secure quantum > channels <https://en.wikipedia.org/wiki/Quantum_channel>.[3] > <https://en.wikipedia.org/wiki/Quantum_Experiments_at_Space_Scale#cite_note-IOP-3> > QUESS > itself has limited communication capabilities: it needs line-of-sight > <https://en.wikipedia.org/wiki/Line-of-sight_propagation>, and can only > operate when not in sunlight.[8] > <https://en.wikipedia.org/wiki/Quantum_Experiments_at_Space_Scale#cite_note-Xinhua-8> > " > > Jim Bell > > > > > On Monday, June 29, 2020, 12:43:08 AM PDT, таракан < > [email protected]> wrote: > > > I quote the main title of the article: > > "*Scientists in China managed to exchange a crypto key at a distance of > over 1,000 kilometers*" > > Wow! > > How can they do that? > > On Monday, 29 June 2020 г., 2:54, jim bell <[email protected]> wrote: > > Cointelegraph: Experts Split on Practical Implications of Quantum > Cryptography.https://cointelegraph.com/news/experts-split-on-practical-implications-of-quantum-cryptography > > > > There is proof inside many peoples' electronics. Proof that a marketing group would contract development of a frightening virus. A virus that responds to peoples' keystrokes and browsing habits, and changes what people see on their devices. A virus that alters political behavior en masse, for profit. > >
