Dirac vs Feynman: Two different physicists. In terms of character and temperament, Paul Dirac (co-winner of the 1933 Nobel Prize in Physics) and Richard Feynman (co-winner of the 1965 Nobel Prize in Physics) were an antithesis of each other. Both, however, were great physicists in their own right. Dirac had an equation named after him. Feynman had no equation to his credit but his squiggly graphical representations of interactions between elementary particles and photons are called Feynman diagrams. They are not in the league of physics equations. What happened when the two superstars met? Were there any interactions at all? Did they in the worst case scenario avoid each other? They met in the autumn of 1961 at the Solvay meeting. In the book The Strangest Man by Graham Farmelo, both of them, had the following Pinter-esque exchanges: Feynman: I am Feynman. Dirac: I am Dirac. [Silence] Feynman: (Admiringly) It must have been wonderful to be the discoverer of that equation. Dirac: That was a long time ago. [Pause] (Editor’s Note: The equation was formulated in 1928) Dirac: What are you working on? Feynman: Mesons. Dirac: Are you trying to discover an equation for them? Feynman: It is very hard. Dirac: (Concluding) One must try. Surprisingly, it was Dirac who had the last word. Feynman showed measured deference. As a matter of interest, Dirac, via his work had proposed the possible existence of magnetic monopole. Wolfgang Pauli (1945 Nobel laureate in Physics) ever so caustic had dubbed him the “Monopoleon”. Brain Clegg in his book 30-Second Quantum Theory reported that in another occasion when Dirac and Feynman met, the former appeared more condescending. Dirac asked Feynman point blank: “I have an equation, do you have one, too?” We know from Graham Farmelo that Dirac had never ever nominated Feynman for a Nobel Prize. He did not nominate any of his Cambridge colleagues either. The only one he had ever nominated was his Russian friend, Pyotor Kapitz, who was the co-winner of the 1978 Nobel Prize in Physics. Quantum Physics: Dirac & Feynman. The problem of Renormalization. As Einstein explains, the electromagnetic field theory of matter gives rise to infinitely high fields (singularities) at the center of the point particle electron. (Albert Einstein) What appears certain to me, is that, in the foundations of any consistent field theory the particle concept must not appear in addition to the field concept. The whole theory must by based solely on partial differential equations and their singularity-free solutions.In the environment of an electrically charged body there is a magnetic field which furnishes an apparent contribution to its inertia. Should it not be possible to explain the total inertia of the particles electromagnetically. The Maxwell equations in their original form do not, however, allow such a description of particles, because their corresponding solutions contain a singularity. Theoretical physicists have tried for a long time (1936), therefore, to reach the goal by a modification of Maxwells equations. These attempts have, however, not been crowned with success. Thus it happened that the goal of erecting a pure electromagnetic field theory of matter remained unattained for the time being, although in principle no objection could be raised against the possibility of reaching such a goal. What appears certain to me, however, is that, in the foundations of any consistent field theory the particle concept must not appear in addition to the field concept. The whole theory must by based solely on partial differential equations and their singularity-free solutions. (Albert Einstein) Richard Feynman avoided this problem with renormalization whereby infinity is subtracted from infinity and the correct experimental result was substituted into the equation. Dirac wrote; Sensible mathematics involves neglecting a quantity when it turns out to be small - not neglecting it just because it is infinitely great and you do not want it! (Paul Dirac) Richard Feynman also knew this; (Richard Feynman, 1985) No matter how clever the word, it is what I call a dippy process! Having to resort to such hocus pocus has prevented us from proving that the theory of quantum electrodynamics is mathematically self consistent. ... I suspect that renormalization is not mathematically legitimate.But no matter how clever the word, it is what I call a dippy process! Having to resort to such hocus pocus has prevented us from proving that the theory of quantum electrodynamics is mathematically self consistent. ... I suspect that renormalization is not mathematically legitimate. (Richard Feynman, 1985) The solution is to realize that spherical waves in Space (scalar waves described in quantum theory) have a finite wave amplitude at the wave-center and thus eliminate the need for a particle to prevent the radius of the field tending to a singularity with infinite field strength. This then also explains Einsteins last comment that The whole theory must by based solely on partial differential equations and their singularity-free solutions. He just needed to consider the Spherical Standing Wave Structure of Matter rather the continuous spherical field structure of matter! The inception of quantum field theory (QFT) is usually dated 1927 with Diracs famous paper on The quantum theory of the emission and absorption of radiation. Here Dirac coined the name quantum electrodynamics (QED) which is the part of QFT that has been developed first. Dirac supplied a systematic procedure for transferring the characteristic quantum phenomenon of discreteness of physical quantities from the quantum mechanical treatment of particles to a corresponding treatment of fields. Employing the quantum mechanical theory of the harmonic oscillator, Dirac gave a theoretical description of how photons appear in the quantization of the electromagnetic radiation field. ( plato.stanford.edu/entries/quantum-field-theory/ ) With the wave structure of matter in mind you can see why Diracs method works. He is basically converting a continuous field (Einstein) into a discrete field using mathematics related to harmonic oscillators, as resonators only exist at discrete frequencies and thus energies. The following quote from Paul Dirac is very important (he was a very smart sensible Quantum Physicist). This statistical interpretation is now universally accepted as the best possible interpretation for quantum mechanics, even though many Quantum Physics: Paul Dirac Biography and Quotes on Quantum Mechanicspeople are unhappy with it. People had got used to the determinism of the last century, where the present determines the future completely, and they now have to get used to a different situation in which the present only gives one information of a statistical nature about the future. A good many people find this unpleasant; Einstein has always objected to it. The way he expressed it was: The good God does not play with dice. Schroedinger also did not like the statistical interpretation and tried for many years to find an interpretation involving determinism for his waves. But it was not successful as a general method. I must say that I also do not like indeterminism. I have to accept it because it is certainly the best that we can do with our present knowledge. One can always hope that there will be future developments which will lead to a drastically different theory from the present quantum mechanics and for which there may be a partial return of determinism. However, so long as one keeps to the present formalism, one has to have this indeterminism. (P.A.M. Dirac, The Development Of Quantum Mechanics Conferenza Tenuta il 14 Aprile 1972, in Roma, Accademia Nazionale dei Lincei, 1974) The central point is that the formalism of particles and fields in space-time is the cause of confusion in Quantum Theory, and leads to the incorrect probability interpretation of the Quantum waves (rather than assuming real waves in Space). I must say that I am very dissatisfied with the situation, because this so called good theory does involve neglecting infinities which appear in its equations, neglecting them in an arbitrary way. This is just not sensible mathematics. Sensible mathematics involves neglecting a quantity when it turns out to be small - not neglecting it just because it is infinitely great and you do not want it! (Dirac, On Quantum Mechanics and Mathematics, 1937) Richard Feynman was obviously also aware of this problem, and had this to say about renormalisation. (Richard Feynman, 1985) But no matter how clever the word, it is what I call a dippy process! Having to resort to such hocus pocus has prevented us from proving that the theory of quantum electrodynamics is mathematically self consistent. ... I suspect that renormalisation is not mathematically legitimate. Albert Einstein was also aware of this problem as he explains in his critique of Lorentzs electromagnetic field theory for electrons (as it is still the same fundamental problem of the particle / electromagnetic field duality). (Albert Einstein, 1936) The inadequacy of this point of view manifested itself in the necessity of assuming finite dimensions for the particles in order to prevent the electromagnetic field existing at their surfaces from becoming infinitely large.The inadequacy of this point of view manifested itself in the necessity of assuming finite dimensions for the particles in order to prevent the electromagnetic field existing at their surfaces from becoming infinitely large. (Albert Einstein, 1936) Feynmans Spherical IN OUT wave theory is largely correct (and of course explains his success) but his error of using vector e-m waves resulted in infinities at the point particle as the radius tended to zero, and this led to the errors of renormalisation. In reality, Matter, as a structure of scalar spherical quantum waves, has a finite wave amplitude at the Wave-Center (as observed) and thus eliminates the infinities and the problems of renormalisation found in Feynmans Quantum Electrodynamics (QED). (See the Work of Wolff at QuantumMatter for a complete explanation.) And Dirac is pretty spot on with this quote about Space / the Vacuum. The problem of the exact description of vacuum, in my opinion, is the basic problem now before physics. Really, if you can’t correctly describe the vacuum, how it is possible to expect a correct description of something more complex? The Wave Structure of Matter solves this problem by describing Space as a continuously connected wave medium. It is the waves in Space that give rise to our observations of matter. Source: therakyatpost/…/dirac-vs-feynman-two-differ…/ And from Geoff Haselhurst On Truth & Reality (Philosopher of Science, Theoretical Physics, Metaphysics: Wave Structure of Matter) spaceandmotion/ Image 1: In 1928 Dirac described the electron in terms of Einsteins Relativity and QM. The Dirac Equation is profoundly beautiful compressed equation. Image 2: credit: Fermilab. P.A.M.Dirac y R.Feynman. Image 3: Feynman diagrams : Particle interactions can be represented by diagrams with at least two vertices. They can be drawn for protons, neutrons, etc. even though they are composite objects and the interaction can be visualized as being between their constituent quarks. A Feynman diagram showing an example of the kind of interaction that binds neutrons and protons together inside the nucleus. The nuclear force, a residual effect of the strong force between quarks is transmitted by the exchange of a quark-antiquark pair, known as a meson (in this case a pi zero meson). Credit: euro-fusion.org
Posted on: Sun, 07 Dec 2014 16:50:12 +0000
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