Recent content by aliens123

  1. A

    Phase space of spherical coordinates and momenta

    Yes. Well, mostly, I think that the problem just needs to be stated more precisely. "Show that if we average out any physical quantity, whose dependence on ##p_\theta## and ##p_\phi## comes only through the kinetic energy of the particle." However, a function ##R(r, \theta...
  2. A

    Phase space of spherical coordinates and momenta

    Sure, but this type of substitution could be done for any F We would still get the factor of $$r^2 \sin \theta$$ if we do this substitution, regardless of what F looks like.
  3. A

    Phase space of spherical coordinates and momenta

    For part A: We need to look at the Jacobian, which is the matrix of partial's: $$J=\frac{\partial(x,y,z,p_x,p_y,p_z)}{\partial(r,\theta,\phi,p_r,p_\theta,p_\phi)}.$$ \begin{align*} x&=r\sin \theta \cos \phi \\ y&=r\sin \theta \sin \phi \\ z&=r\cos \theta \\ p_x = m\dot{x} &= m\dot{r} \sin \theta...
  4. A

    I Electric Field seen by an observer in motion

    I believe that the following transformation (as in the article): Is obtained by making the identifications $$E' = F'_{i 0}, E = F_{j 0}, i, j \in \{1, 2, 3\}$$
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    I Electric Field seen by an observer in motion

    I am not saying that these should be equal. The use of the term "Lorentz transformation" perhaps should not have been used. But the formula in the link considers the following "transformation": $$F_{\mu 0} \mapsto F'_{\mu 0}$$ I should note that the author does not use the term "Lorentz...
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    I Electric Field seen by an observer in motion

    This doesn't seem to agree with PeterDonis. He is saying the Lorentz transformation relates the components of \uE according to u^a with the components of \uE according to v^a .
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    I Electric Field seen by an observer in motion

    If this is the case, then why isn't the Lorentz transformation given in this link: https://webhome.phy.duke.edu/~rgb/Class/phy319/phy319/node136.html Related by a "simple" Lorentz transformation? That is, ##(E_G)_\mu \mapsto (E_G)'_\mu## Is just $$(E_G)_\mu = (E_G)'_\alpha \Lambda_{\mu}^{\ \...
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    I Electric Field seen by an observer in motion

    Okay, so the transformation given in this link: https://webhome.phy.duke.edu/~rgb/Class/phy319/phy319/node136.html Does not answer the question: "If I am at rest in frame G, then boost to frame H, what will be the new electric field I measure?"
  9. A

    I Electric Field seen by an observer in motion

    Let me try to be more clear. Suppose we have two observers G and H. Let observer G be at rest in the unprimed frame, and let H be at rest in the primed frame. There are two different covariant quantities: the electric field measured by observer G, and the electric field measured by observer H...
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    I Electric Field seen by an observer in motion

    What does the Lorentz transformation equation for the E field tell you, if not the components of the E field in the observer's frame?
  11. A

    I Electric Field seen by an observer in motion

    The statement which you are saying is not correct is literally what Wald said.
  12. A

    I Electric Field seen by an observer in motion

    When I first read this I didn't understand what you were trying to see but it appears crystal clear in hindsight
  13. A

    I Electric Field seen by an observer in motion

    Oh okay I think I see. So would it be correct to say that Is the electric field seen by an observer with 4-velocity ##v^a##. And Is also the electric field seen by an observer with 4-velocity ##v^a##, but they appear to be different because they have different components because they have a...
  14. A

    I Electric Field seen by an observer in motion

    Well, yes; I'm aware that there is no conflict. As I interpret Wald's statement there is a conflict. I know that there is no conflict. So I know that I am misinterpreting Wald's statement. Hence my question.
  15. A

    I Electric Field seen by an observer in motion

    The second part of my post is the random internet post. How can that be both correct and not correct? In the first part of my post I do not try to transform the EM field tensor.
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