linkstream2 microblog

https://en.wikipedia.org/wiki/First_Draft_of_a_Report_on_the_EDVAC
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Von Neumann describes a detailed design of a “very high speed automatic digital computing system.” He divides it into six major subdivisions: a central arithmetic part, CA, a central control part, CC, memory, M, input, I, output, O, and (slow) external memory, R, such as punched cards, Teletype tape, or magnetic wire or steel tape. The CA will perform addition, subtraction, multiplication, division and square root. …Von Neumann’s design is built up using what he call “E elements,” which are based on the biological neuron as model,[1][2] but are digital devices which he says can be constructed using one or two vacuum tubes. In modern terms his simplest E element is a two-input AND gate with one input inverted (the inhibit input). …The treatment of the preliminary report as a publication (in the legal sense) was the source of bitter acrimony between factions of the EDVAC design team for two reasons.[3] First, publication amounted to a public disclosure that prevented the EDVAC from being patented; second, some on the EDVAC design team contended that the
stored-program concept had evolved out of meetings at the University of Pennsylvania’s Moore School of Electrical Engineering predating von Neumann’s activity as a consultant there, and that much of the work represented in the First Draft was no more than a translation of the discussed concepts into the language of formal logic in which von Neumann was fluent. Hence, failure of von Neumann and Goldstine to list others as authors on the First Draft led credit to be attributed to von Neumann alone. (See Matthew effect and Stigler’s law.) “}}

https://en.wikipedia.org/wiki/Harvard_Mark_III

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The Harvard Mark III, also known as ADEC (for Aiken Dahlgren Electronic Calculator) was an early computer that was partially electronic and partially electromechanical.
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https://www.britannica.com/biography/John-von-Neumann/Princeton-1930-42
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Never much like the stereotypical mathematician, he was known as a wit, bon vivant, and aggressive driver—his frequent auto accidents led to one Princeton intersection being dubbed “von Neumann corner.” “}}

https://en.wikipedia.org/wiki/Lise_Meitner

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At that point we both sat down on a tree trunk (all that discussion had taken place while we walked through the wood in the snow, I with my skis on, Lise Meitner making good her claim that she could walk just as fast without), and started to calculate on scraps of paper. The charge of a uranium nucleus, we found, was indeed large enough to overcome the effect of the surface tension almost completely; so the uranium nucleus might indeed resemble a very wobbly unstable drop, ready to divide itself at the slightest provocation, such as the impact of a single neutron. But there was another problem. After separation, the two drops would be driven apart by their mutual electric repulsion and would acquire high speed and hence a very large energy, about 200 MeV in all; where could that energy come from? Fortunately Lise Meitner remembered the empirical formula for computing the masses of nuclei and worked out that the two nuclei formed by the division of a uranium nucleus together would be lighter than the original uranium nucleus by about one-fifth the mass of a proton. Now whenever mass disappears energy is created, according to Einstein’s formula E = mc2, and one-fifth of a proton mass was just equivalent to 200 MeV. So here was the source for that energy; it all fitted![98]
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https://en.wikipedia.org/wiki/Ergodic_theory#Mean_ergodic_theorem
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A central concern of ergodic theory is the behavior of a dynamical system when it is allowed to run for a long time. The first result in this direction is the Poincaré recurrence theorem, which claims that almost all points in any subset of the phase space eventually revisit the set. Systems for which the Poincaré recurrence theorem holds are conservative systems; thus all ergodic systems are conservative. More precise information is provided by various ergodic theorems which assert that, under certain conditions, the time average of a function along the trajectories exists almost everywhere and is related to the space average. Two of the most important theorems are those of Birkhoff (1931) and von Neumann which assert the existence of a time average along each trajectory. For the special class of ergodic systems, this time average is the same for almost all initial points: statistically speaking, the system that evolves for a long time “forgets” its initial state. Stronger properties, such as mixing and equidistribution, have also been extensively studied.
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https://en.wikipedia.org/wiki/Reinhold_Bertlmann

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In 1978 Bertlmann went to CERN, where he worked together with J. S. Bell.[1] Bertlmann always wore socks of different colours. In 1981 Bell wrote the article “Bertlmann’s socks and the nature of reality”, where he compared the EPR paradox with Bertlmann’s socks: if you observe one sock to be pink you can predict with certainty that the other sock is not pink. Thus you might assume that quantum
entanglement is just the same. However, this is a non-admissible simplification, and Bell in his article explains why.[2]
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https://en.wikipedia.org/wiki/Fat_Man

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Oppenheimer brought John von Neumann to Los Alamos in September 1943 to take a fresh look at implosion. After reviewing Neddermeyer’s studies, and discussing the matter with Edward Teller, von Neumann suggested the use of high explosives in shaped charges to implode a sphere, which he showed could not only result in a faster assembly of fissile material than was possible with the gun method, but which could greatly reduce the amount of material required, because of the resulting higher density.[8] The idea that, under such pressures, the plutonium metal itself would be compressed came from Teller, whose knowledge of how dense metals behaved under heavy pressure was influenced by his pre-war theoretical studies of the Earth’s core with George Gamow.[9] The prospect of more-efficient nuclear weapons impressed Oppenheimer, Teller, and Hans Bethe, but they decided that an expert on explosives would be required. Kistiakowsky’s name was immediately suggested, and Kistiakowsky was brought into the project as a consultant in October 1943.[8]
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https://en.wikipedia.org/wiki/Eigenfunction

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In the study of signals and systems, an eigenfunction of a system is a signal f(t) that, when input into the system, produces a response y(t) = λf(t), where λ
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https://en.wikipedia.org/wiki/Paul_Dirac#:~:text=Dirac%20was%20known%20among%20his,was%20one%20word%20per%20hour.
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Dirac was known among his colleagues for his precise and taciturn nature. His colleagues in Cambridge jokingly defined a unit called a “dirac”, which was one word per hour.
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https://en.wikipedia.org/wiki/Heligoland

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Werner Heisenberg (1901–1976) first formulated the equation underlying his picture of quantum mechanics while on Heligoland in the 1920s. While a student of Arnold Sommerfeld at Munich in the early 1920s, Heisenberg first met the Danish physicist Niels Bohr. He and Bohr went for long hikes in the mountains and discussed the failure of existing theories to account for the new experimental results on the quantum structure of matter. Following these discussions, Heisenberg plunged into several months of intensive theoretical research but met with continual frustration. Finally, suffering from a severe attack of hay fever, he retreated to the treeless (and pollenless) island of Heligoland in the summer of 1925. There he conceived the basis of the quantum theory.
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