Jump to content


Senior Members
  • Posts

  • Joined

  • Last visited

Everything posted by juanrga

  1. That is a non-technical book for broad audiences where he makes many jokes invent names as the "Hub" appeal to The Matrix of pop culture... As explained before the wave-particle duality myth is very popular in historical and popular treatises. Wilczek has a paper (Quantum field theory), published in Reviews of Modern Physics, where he revises the fundamental principles of what he considers "a complete foundation for atomic physics and chemistry". He never mention duality, consider electrons and photons as particles, and explains how the original wave-functions of Dirac are abandoned in favour of field operators. I am glad that we agree on those. The ordinary QM of particles explains how a single electron interfere with itself (the technical explanation is other) and how the interference pattern in (e) is obtained when the experiment is repeated with thousand of electrons. There is not interference pattern in (a) as is self-evidently. No, the same pattern is not formed by "waves", this is the reason which quantum mechanics was developed to explain this and other experiments.
  2. An electron is a particle. A particle is a physical system, neither a kind of motion nor a kind of function. As stated before, the ordinary quantum mechanics of particles explains the interference patterns observed when thousands of particles impact a screen in a double-slit experiment. Yes, an electron can be excited and form interference patterns, and both of those things happen in quantum wave mechanics. Yes, an electron can be excited, but above I wrote about the excitation of a field. An electron alone does not form an interference pattern. Eleven electrons do not form an interference pattern (a). Thousands of electrons form an interference pattern (e). Yes, the quantum 'wave' mechanics of particles can explain some aspects of excited electrons and can explain some aspects of interference patterns. As stated before, more general quantum mechanical formulations can explain other aspects beyond the quantum 'wave' mechanics formulation.
  3. There are not "oscillation patterns" because the electron is not oscillating. The ordinary quantum mechanics of particles explains the well-known interference patterns observed when thousands of particles impact a screen in a double-slit experiment. Next is the sequence of patterns obtained when the experiment is repeated; each white point is where one electron impacted the photographic screen. (e) is the observed interference pattern when a large number of electrons has already impacted the photographic screen. The electron is never "an oscillation in a matter field". There is an old interpretation in quantum field theory, where an electron is an excitation of a fermionic field. But modern formulations do not support this view and fermionic fields are derived as unobservable systems, when doing certain approximations in the interaction Hamiltonian of a system of particles (electrons).
  4. All the references state that an electron is a particle not a wave. A particle can oscillate and it continues being a particle, not a wave. A particle has angular momentum and energy and continues being a particle not a wave. Dirac also agree on that the electron is a particle.
  5. Do you know why the electrical conductivity for NaOH is greater than for KOH for different concentration in mass percent (range 0.5%--5%), but the electrical conductivity at infinite dilution of the K+ is quoted to be greater than for Na+? Someone has the theory this is due to ion pairing, but is not ion pairing in 1:1 electrolytes at low concentration an unimportant effect?
  6. A thing that has always surprised me about this natural vs non-natural division is why some people insists on considering humans how something outside of nature. Once you acknowledge that nature include humans, as a kind of living beings, everything is made of the same particles.
  7. Maybe it is worth to mention that chemists also know that the electron is a particle. Indeed the International Union of Pure and Applied Chemists gives the following official definition of the electron: It must be interesting to add that the Particle Data Group has an entry devoted to the electron. That entry gives the last measured data about the electron http://pdg.lbl.gov/2...s_listings.html The citation is 2011 Review of Particle Physics. Please use this CITATION: K. Nakamura et al. (Particle Data Group), J. Phys. G 37, 075021 (2010) and 2011 partial update for the 2012 edition. This is an article by Weinberg stating that the electron is a particle and critizing the old idea of particles as excitation of fields. Some more resources stating that the electron is a particle http://www.web-books...MParticles.html And more giving only the links: http://en.wikipedia....st_of_particles http://www.particlep...dard-model.html http://www.particlep...-particles.html http://ctp.berkeley..../neutrino3.html http://www.arpansa.g...glossary.cfm#e7 http://www.nap.edu/o...d=6045&page=161 http://education.yah...ntry/elementr-p And finally I would like to add a Nobel Lecture by Dirac. This is particularly delicious, because Dirac uses the old relativistic wave mechanics that he developed (recall that he wrote this in 1933!), but emphasizes to a broad public that electrons are... particles:
  8. The part that you repeat above says "the electron is an elementary particle" and this exactly what I have said. No contradiction here. The informal poll that you quote is not particle versus wave, but particle versus field. A field is an infinite collection of particles and, by definition, is unobservable. Particles are observed each day. From your post #19 First, the part that you quoted is in the context of a historical description of how the subject was born. By "In its mature form" Weinberg refers to the work done about the 30s. The whole quote, including historical context, is: Second, as explained above the quote that you reproduce is an old vision about quantum field theory and particles. Precisely Weinberg, writes after the part that you quoted: Third, Weinberg confirms my point that an electron is a particle and he does in several parts of his talk: Neumaier is not right regarding the fundamental nature of fields. Being a mathematician Neumaier also omits to say that fields are not observable, unlike particles. Yes, I read the last paragraph. However, in another part Neumaier contradicts to himself and agrees with me on that both photons and electrons are particles. http://www.mat.univi...faq/topics/free Apart from the several textbooks cited, the CERN website, the Weinberg talk, Neumaier FAQ, and myself explaining that the electron is a particle, you can find the same in lot of encyclopedias, academic websites, and online general dictionaries http://scienceworld....s/Electron.html http://physics.about.../g/electron.htm http://hyperphysics..../lepton.html#c2 http://hyperphysics....s/spinc.html#c2 http://www.merriam-w...ionary/electron http://www.thefreedi...ry.com/electron http://dictionary.re...browse/electron http://www.pbs.org/w...nt/part-nf.html http://public.web.ce...ossary-en.php#L http://www.pas.roche...le_physics.html http://www.britannic...ectron-muon-tau http://hepwww.rl.ac....l/glossary.html http://burro.cwru.ed...rticlephys.html http://www-sldnt.sla...ndard_model.htm See also the newspaper presentation My favourite particle: the electron
  9. emphasis added. Kinda proves my point. Maybe I would have added that the generalization in that paper allows for a precise characterization of unstable particles, but it reduces to the particle physics definition for stable particles as the electron. Some relevant extracts from that link: And the corresponding article http://en.wikipedia..../Point_particle also contains relevant statements, which I reproduce next:
  10. After saying that an electron is a wave (a plain wrong statement), are you trying to say now that water is also a wave?
  11. I do not wait to convince to people who cannot be convinced, but at least it would be fair if the "you made" is changed to "thousands of scientists, including you, made". Already in #162 (i.e. the post just before the your) you can find quotes and link from CERN website stating that the electron is a particle.
  12. I think that I do not need to argue about something that I have not said. In fact, I cited a paper that introduces a generalization of the concept of particle used in particle physics.
  13. I have no comments on that "formal definition". I do see where the literature very clearly states that 'Dualism' or 'Duality' or 'Wave-Particle Duality' from the historical view is incorrect. I think Messiah made statements that attempted to address this and is what I posted earlier. I do not however see anything that explicitly supports your statements that electrons are particles and not waves. I've seen literature that more explicitly states that electrons are waves except in certain experimental conditions where one would treat them exclusively as particles and not wave particles. I also believe that the deeper abstraction supports this view and not the one that you are trying to condition. Therefore, you saying me that when you go to the CERN glossary and read stuff as You "do not however see anything that explicitly supports your statements that electrons are particles and not waves." It seems evident that further discussion must be useless. No?
  14. First a remark: I am not giving my own definition of particle. I am alluding to the standard definition of particle used in a branch of science named particle physics. It is this standard definition which Weinberg alludes to, when he emphasizes that "the electron is a particle" and when writes "The quantum theory of particles like electrons". When Weinberg writes in his talk that he starts with "Wigner's definition", he means Wigner definition of particle. It is this standard definition of particle which leads to Weinberg to say in his talk that the "old dualism" is "safely dead and will never return". This is the standard definition of particle used by guys at CERN when write, in their own website, that electrons are particles and that: Evidently, CERN guys do not mention old myths as "dualism", "matter waves", and all that outdated and nonsensical stuff. I have given a table of elementary particles in #114. Composite particles are made of elementary particles. For instance a proton is made of 2 quark-up plus 1 quark-down. About the link, I just click in the link in the above post and it works for me, opening a new tab in my FF browser with the next webpage from Google Books:
  15. I have prepared a draft about Stochastic scientific quantities and states. It includes the usual material (variances, medians, fluctuations, correlations), but I have added material which is not discussed in usual statistical physics literature, such as the stochastic Schrödinger equation. I have included an important remark by NG van Kampen about misconceptions regarding the concept of ensemble and some other criticism. If you find some mistake let me know. Criticism and suggestions are welcomed.
  16. Man hat im 1987 diese buch verlangt. Is this modern? If you read the OP, the textbook by Greiner et al. was already cited [5] in the first version of the draft. The modern textbook which I have added to the new draft is the reference [6]:
  17. I replied to you in #95, stating that I did not understand your question. You never care to re-phrase or explain it. I do not still understand what do you mean by "a formal definition of charge". I only can guess that you mean "electric charge" and not "color charge" but little more... You may believe that "there are many holes" in the statements done by me, by Weinberg in his talk, or in the statements found in the CERN website, but reality must be rather different. Albert Messiah's QM is a dated textbook. QM is based in a set of postulates (see e.g. Cohen textbook or Weinberg textbook cited before), none of which is a "principle of complementarity". The rest of your quotation (specially the bold part) was already answered before in #56, using a quotation from an editor of the Wikipedia. I reproduce the quote from him: Finally, about Ryder, your own words were: Already in #5 I emphasized that different theories give different meaning to different terms and that one would not mix concepts: The change was done because problems with the previous concepts were found in the lab and better concepts and theories were developed. The problem does not seem to be one of semantics, but twofold. At the one hand, some of people believes that outdated concepts/theories/books have the same status than modern ones. At the other hand, some people do not read my posts. One folk has recently stated that I never used the word "elementary" before, when I did... and more than one time. If you believe that particle physicists claims such as "the electron is a particle" "Everything around us is made of matter particles" are not universal or need correction, please indicate us some amount of matter which is no made of the known particles in the table given before. As stated before, particle physicists have given precise definitions of what is and what is not a particle (either composite or elementary). Weinberg in his talk writes about what is a particle. Myself have given the properties that define specific particles (mass, charge, spin...) and given a table with all known particles plus some hypothetical. I also stated that the definition of particle is found in textbooks. I cite a pair of relevant textbooks, including Weinberg one. In this book we can find a definition of quantum particle http://books.google....ducible&f=false I also give a Adv. Chem. Phys. article explaining how quantum mechanics has to be generalized for dealing with unstable particles... Regarding your allusion to arrogance. The only arrogance that I can find here becomes from posters who believe that a Nobel laureate as S. Weinberg or a worldwide expert center as CERN are wrong when claim that an electron is a particle and that everything is made of particles. The 'argument' given by this posters is a vague allusion to the well-known interference experiments. I find arrogant that those posters pretend that Weinberg-CERN are wrong because do not know what is an interference experiment! I give it again now. And add a textbook link
  18. The definition of (elementary) particle was implicitly stated in #131 using a quote from Weinberg's talk. I already used the term "elementary" in #93. The electron is an elementary particle the proton is a composite particle, both are particles.
  19. When Weinberg writes in his talk and when the CERN folks write in their website They are not using ambiguous and imprecise words from a non-scientific online dictionary as you do. They are using the precise definition of elementary particle used in fundamental physics. A precise definition to which I alluded several times before in this thread but that seems that 'nobody' knows here
  20. A new version of the draft is available. After discussion and comments in this thread, I have given more complete quotations of Greiner, Neise, & Stöcker and next a general background about what is the law of conservation of energy and what is not. I have added a citation to the textbook cited in this thread and corrected another mistake by Greiner, Neise, & Stöcker regarding the first law of thermodynamics for open systems. The draft includes corrections, provided by Dr. Matta, to the part about proper open quantum systems. Comments, suggestions, and corrections are welcomed.
  21. No interpretation issue is here. Someone else said in this thread "the electron is a wave". I said that his claim is nonsense, because the electron is a particle and Weinberg in the same talk that you cite writes Case closed.
  22. It is your definition of science which needs revision: http://publications.nigms.nih.gov/chemhealth/atoz.htm http://es.scribd.com/doc/21610005/5/GREEN-CHEMISTRY-AND-SYNTHETIC-CHEMISTRY
  23. When Weinberg states that "the electron is a particle" he is not saying, not even insinuating, that was a "little sphere". In fact, Weinberg gives the definition of particle in his talk, but you missed that part as well...
  24. It is saying that if the heat capacity C is negative the second derivative of the entropy with energy is positive. This means that the entropy function has form of "U" and there is not maximum entropy corresponding to equilibrium. For any material the heat capacity is positive and the entropy function has form of inverted U _ / \ with a maximum corresponding to equilibrium.
  25. That percent of dark matter is obtained from the difference between the observation and the prediction done using GR. If instead GR you use some other theory, then you do not need dark matter to explain the observations. Regarding CMB, precisely MOND was the only theory that predicted the correct first and second peaks (ligth blue), whereas the dark matter model (orange) failed After the CMB data become available, dark matter theorists changed the dark matter model to fit the data a posteriori. The problem is that they are using now some parameter values in disagreement with other tests.
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.