Recent content by lriuui0x0

  1. L

    I Jacobi identity of Lie algebra intuition

    My intuition about the Lie algebra is that it tries to capture how infinitestimal group generators fails to commute. This means ##[a, a] = 0## makes sense naturally. However the Jacobi identity ##[a,[b,c]]+[b,[c,a]]+[c,[a,b]] = 0## makes less sense. After some search, I found this article...
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    I Can configuration space be observer independent?

    Sorry, the question may sound a bit weird. I will try to give a more detailed explanation on what structure I have in mind before rasing the question. So first, we have a 4d spacetime, there are n worldlines in the spacetime representing n particles forming a system with certain interation...
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    I Can configuration space be observer independent?

    I just don't usually see coordinate independent formulation of the configuration space.
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    I Can configuration space be observer independent?

    We can formulate the spacetime in an observer/coordinate independent way, i.e. a particle becomes a worldline in the 4d space. Then relative to each observer, the worldline can be casted to a function in R^3. However, I haven't found any reference on formulating configuration space in a...
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    I Galilean transformation of non-inertial frame

    I think I started to understand why it's an unnatural thing to think about Galilean transformation on non-inertial observers, because the Galilean group naturally applies to the set of all inertial observers and is in one-to-one relationship to it (not sure what's the right math word here?). I...
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    I Galilean transformation of non-inertial frame

    What I originally had in mind is below: So we have an affine spacetime ##N^4##, the associated vector space ##V^4##, with the simultaneity subspace ##V^3##. An oberserver in my mind is the combination of a smooth worldline ##\gamma: \mathbb{R} \to N^4## and a smooth orthonormal basis assignment...
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    I Galilean transformation of non-inertial frame

    Hmmmm...there must be something I understood wrongly on this (why Galilean transformation is not applicable to non-inertial frame). I will try to be a bit more explicit: Let's say the world is the 4 dimensional space with Galilean structure defined in the Arnold's. A Galilean transformation is...
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    I Galilean transformation of non-inertial frame

    Actually given the transformation is Galilean, shouldn't the ##\mathbf{a}_1## and ##\mathbf{a}_2## be the same, up to an orthogonal transformation?
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    I Galilean transformation of non-inertial frame

    If we take the definition from Arnold's The galilean group is the group of all transformations of a galilean space which preserve its structure. The elements of this group are called galilean transformations. Thus, galilean transformations are affine transformations of A^4...
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    I Galilean transformation of non-inertial frame

    It's frequently discussed Galilean transformation brings one inertial frame to another inertial frame, and such a transformation leaves Newton's second law invariant (of the same form). I wonder what happens for non-inertial frame? If we start with a non-inertial frame, and Galilean transform...
  11. L

    Relativity Special relativity in Lagrangian and Hamiltonian language

    That's a really good recommendation! I wonder if there're classical mechanics books that follows a similar philosophy? E.g. starting from a mathematical formulism in coordinate free langauge. Thanks! I watched Susskind's lectures before but I'm looking for something with a bit more mathematical...
  12. L

    I Reference frame vs coordinate system

    It's this book https://link.springer.com/book/10.1007/978-3-642-37276-6
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    I Reference frame vs coordinate system

    I found some new reference on this. In book "Special Relativity in General Frame", the concept of "local frame" is defined, similarly the concept of observer, in section 3.4. I wonder if this is a common definition, and does it generalise to GR well?
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    I Anyone knows why musical isomorphism is called so?

    Ooops, just thought there might be some interesting reasons for this name. Let's close this thread....
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    I Anyone knows why musical isomorphism is called so?

    Anyone knows why musical isomorphism is called so? Why is it musical? https://en.wikipedia.org/wiki/Musical_isomorphism
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