Recent content by jordi

  1. J

    Quantum An alternative route to learn mathematics for physics, the "rigorous way"

    This seems like choosing a profession. Nothing bad about this, but in my case, I am not speaking about being successful professionally, but about the pleasure to learn, and the pleasure to be able to answer the why why why questions.
  2. J

    Quantum An alternative route to learn mathematics for physics, the "rigorous way"

    I do not disagree with your comment. Having said that, I repeat the issue of motivation. Maybe some (lucky) students do not need motivation to learn analysis, and they blindly believe the axioms of the real numbers, and everything goes well starting from there. But some others may be...
  3. J

    Quantum An alternative route to learn mathematics for physics, the "rigorous way"

    Of course, I do not disagree with you. But what I have said might be useful to at least two kind of people: 1. Students that find difficult to get motivation to start studying analysis from the axioms of the real numbers. This is extremely unmotivated. One could say that mathematical maturity...
  4. J

    Applied Mathematics for physicists books (poll)

    I like "big Hassani", but I have voted for other: Szekeres.
  5. J

    Quantum An alternative route to learn mathematics for physics, the "rigorous way"

    What I am going to outline should not be seen as a recommendation for most. Probably only a minority would benefit from it. One possibility to learn the necessary maths to study physics, from a "mathematical physics" point of view is to first study a degree in maths (and maybe also a Master...
  6. J

    A How do you view Physics as a whole?

    Sure, but how do you prove that these small quantum fluctuations never become macroscopically large? (as it happens in reality). Also, there is another issue (maybe this one is well understood, and only my knowledge is faulty): CM observes the positions of objects. By observing how the Moon...
  7. J

    A How do you view Physics as a whole?

    https://aapt.scitation.org/doi/10.1119/1.4751274#:~:text=88.,x%2Ct)%3D0.
  8. J

    A How do you view Physics as a whole?

    There are many arguments for this limit (Ehrenfest theorem, WKB approximation, hbar to 0 in the path integral ...) but I think the lack of spread of the wave packet is not easy to explain, in this limit. I have read (I do not know how certain this claim is) that it is not obvious that CM can be...
  9. J

    A How do you view Physics as a whole?

    Usually it is stated that physics is divided among classical mechanics, classical field theory, quantum mechanics, quantum field theory and statistical mechanics, with hbar, the speed of light and the number of particles being the parameters differentiating all these theories. However, despite...
  10. J

    Is it possible to get a Mentor for personal mentorship?

    AI? Artificial intelligence? I think I need more like a "human intelligence", more on the "emotional" side ... :)
  11. J

    Is it possible to get a Mentor for personal mentorship?

    I am a person working in the private sector. I studied physics, up to MSc level (QFT, string theory). But then I moved towards the private sector, raising a family, etc. My wish is to try and understand QFT at the non-perturbative level. I do not need to write any paper on that subject, just to...
  12. J

    A Lattice QED

    Thank you for the explanation, Neumaier. Do you have any way to reconcile the idea that lattice QCD seems to be a good definition for "non-perturbative QCD", but instead, lattice QED seems not to be a good definition for "non-perturbative QED"? Intuitively, I would expect the lattice method to...
  13. J

    A Lattice QED

    This thread is old. But I am surprised to read that lattice QED does not need to be the "correct" non-perturbative quantum version of QED (apparently, lattice QED is trivial, but perturbative QED gives correct results, and Neumaier argues that it could be QED is a perfectly fine quantum theory...
  14. J

    Quantum gravity and quantum cosmology books

    I want to ask for opinions about the suggested path to be able to study the book "Quantum Fields and Strings" successfully, from a mathematical physics point of view. Maybe with a first entry with the books of Costello, Hall and Folland. My interest is as an amateur (financial professional)...
  15. J

    A An additional constraint to the ZFC axioms?

    I think I have a solution: In the Appendix of Leary's "A friendly introduction to mathematical logic", it is stated: "Think of a set as a collection of objects. If X is a set, we write a 2 X to say that the object a is in the collection X. For our purposes, it will be necessary that any given...
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