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janneseti Send message Joined: 14 Oct 09 Posts: 14106 Credit: 655,366 RAC: 0 |
Richard Feynman’s apocryphal declaration: “If you think you understand quantum mechanics, you don’t understand quantum mechanics.†|
William Rothamel Send message Joined: 25 Oct 06 Posts: 3756 Credit: 1,999,735 RAC: 4 |
I think the quantum world is one of those places that is stranger than I can imagine. And I can imagine some pretty strange things. What bother's me most is that there are very few clear explanations about exactly what is the wierdness and how we know that it is wierd. Also why we think that quantum computers will work better that today's digital computers. |
tullio Send message Joined: 9 Apr 04 Posts: 8797 Credit: 2,930,782 RAC: 1 |
Quantum computers are ideally more powerful than today's computers. But as of today they do not exist, except in the marketing of D-Wave, a Canadian firm which has sold them to NASA and Google for a few million bucks. Tullio |
janneseti Send message Joined: 14 Oct 09 Posts: 14106 Credit: 655,366 RAC: 0 |
There are some further explanations here. http://indianexpress.com/article/explained/china-launches-quantum-communication-micius-satellite-2989406/ http://www.sciencemag.org/news/2017/06/china-s-quantum-satellite-achieves-spooky-action-record-distance Quantum computers are very useful in finance and military cryptography applications. You cannot eavesdrop the communication. The quantum computer, which could decode current keys in a flash, lags far behind the simpler project of quantum key-pair encryption. The idea is to create and share a pair of entangled photons which serve as keys (Micius will beam photons to stations in China and Austria). A conventional key cannot signal that it has been cracked, but because of the observer effect, an attempt to intercept a quantum key would reduce it to junk data. So it’s the end of the line for bank fraud and online espionage, which infiltrate the web of trust which protects Internet communications. |
tullio Send message Joined: 9 Apr 04 Posts: 8797 Credit: 2,930,782 RAC: 1 |
Quantum cryptography is a reality used for keys distribution. Quantum computers are just laboratory experiments, with the possible exception of D-Wave, which is contested by scientists. Tullio |
tullio Send message Joined: 9 Apr 04 Posts: 8797 Credit: 2,930,782 RAC: 1 |
A new particle, made up from two "charm" quark and one "up" quark has been discovered by LHC in Geneva. The spokesman for the LHCb experiment, Giovanni Passaleva, has announced it at a meeting of The European Physical Society in Venice. The new particle is called Xicc++ and has a mass of 3621 MeV. The charm quarks are heavier than the up quark, so this is like a planet around a double star. Tullio |
tullio Send message Joined: 9 Apr 04 Posts: 8797 Credit: 2,930,782 RAC: 1 |
According to theregister.co.uk China's Experimental Advanced Superconducting Tokamak has reached a plasma temperature of 50 million Kelvin and maintained it for 101.2 s. If confirmed, this is a record for all Tokamaks. Tullio |
Bob DeWoody Send message Joined: 9 May 10 Posts: 3387 Credit: 4,182,900 RAC: 10 |
So, does this mean that China will beat the rest of the world to a working fusion power plant? Bob DeWoody My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events. |
tullio Send message Joined: 9 Apr 04 Posts: 8797 Credit: 2,930,782 RAC: 1 |
They intend to go to a 1000 s of plasma confinement time and then build a demonstration plant. The only variable missing is the plasma density they have achieved. The Lawson criterion considers the product of plasma density, plasma temperature and confinement time, so I cannot tell if they have achieved the Lawson goal. But they seem to be on the right road and are certainly ahead. Tullio |
Wiggo Send message Joined: 24 Jan 00 Posts: 34744 Credit: 261,360,520 RAC: 489 |
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tullio Send message Joined: 9 Apr 04 Posts: 8797 Credit: 2,930,782 RAC: 1 |
ITER ia a big machine, but it is not a stellarator but a Tokamak. I've seen one of its superconducting magnets shipped from Liguria in Italy on a ship bound to Provence. The leading stellarator I know is Wendelstein II in Garching, Germany. Tullio |
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