Recent content by formodular

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    A Another action for the relativistic particle

    You are analyzing a constrained dynamical system, and it is commonly said that 'first class constraints are generators of gauge transformations', e.g. section 1.4 of Henneaux 'Quantization of Gauge Systems'. On a classical level, they are not commonly written in exponential form like that...
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    I Solve the particle in a box problem using matrix mechanics?

    The particle-in-a-box problem from the pov of matrix mechanics seems to be discussed in section 7.5 of Razavy's 'Heisenberg's Quantum Mechanics' which cites this paper, it looks very non-trivial.
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    A Another action for the relativistic particle

    Your article is a discussion of the GSW equation (2.1.5) I mentioned above, however GSW introduce it out of thin air and the article introduces the einbein basically via magic. The fool-proof way to arrive at the einbein form of the action, the way that generalizes, is discussed from equations...
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    A Another action for the relativistic particle

    It's just the einbein form of the action for a point particle, e.g. eq. (2.1.5) of GSW (note the action you posted is technically zero for massless particles, one adds in the constraint p^2 = - m^2 as a Lagrange multiplier then eliminates momentum to get the action as in (7.1)).
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    A Physical Motivation for Supersymmetry

    The GL paper http://www.jetpletters.ac.ru/ps/1584/article_24309.shtml one of the first papers on what became known as supersymmetry, introduced the idea by noting that only a fraction of the possible interactions invariant under the Poincare group are realized in nature, hence it may be that...
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    A First order formalism of Polyakov action

    The Hamiltonian is introduced in the calculus of variations as part of breaking up a 2nd order ode into a system of first order ode's, and of course one knows the Hamiltonian is related to the Lagrangian by a Legendre transform, ##L = p \dot{x} - H##, where now the derivatives are at most of...
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    A 11 coordinate system for separation of variables

    The result, summarized in Eisenhart - Separable Systems in Euclidean 3-Space seems to be proven in https://www.jstor.org/stable/1968433 and seems to depend on https://www.jstor.org/stable/2306278 If anyone goes through these and gets a sense of the idea of the theorem, proof and where it...
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    A Weyl transformation of connection and curvature tensors

    Peeling ##\Omega^{-2} g^{bd}## off ##I## and ##V## easily gave me the ##\Omega^{-2}## terms in Zee's Ricci scalar, the other three should give the ##\Omega^{-1}## part which I can check another day but there should be no issue.
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    I Why does Special Theory of Relativity leave out Potential Energy?

    One can add potentials in SR: to add scalar potentials one considers the action ##S = - mc \int ds## we and on adding a scalar potential ##-\int V(x^{\mu}(\tau)) d \tau##, with ##\tau## proper time, this leads to ##S = - mc \int ds - \int V \frac{d s}{c} = - c \int (m + \frac{V}{c^2}) ds##. The...
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    A Weyl transformation of connection and curvature tensors

    I believe you are right, in exponential form those factors from the Christoffels cancel so unfortunately I'm not sure where you're going wrong without basically re-doing it in this notation. I have a write-up of the conformal transformation of the Ricci scalar in Zee's notation attached in a...
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    A Weyl transformation of connection and curvature tensors

    Your Christoffel symbols do not account for the fact that ##g_{ab} \to e^{\Omega} g_{ab}## implies ##g^{ab} \to e^{-\Omega} g^{ab}##, so the Christoffel symbols (compare to those in the wiki link), and especially the derivatives of the Christoffel symbols, are off. Taking the conformal factor to...
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    Unraveling Landau's Mechanics: Why is Space Isotropic?

    The point is very simple: velocity is described by a vector, a vector points in a certain direction - if the Lagrangian is to be a direction-independent function of velocity the Lagrangian can only depend on the velocity vector in a way that eliminate the notion of directionality associated to...
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    I What is SR transformarion for bispinor?

    The anti-symmetric tensor is built from the direct product of a dotted spin ##k = \tfrac{1}{2}## and an un-dotted spin ##l=\tfrac{1}{2}## ##\mathrm{SL}(2,\mathbb{C})## spinor, in which case it has ##(2k + 1)(2l + 1) = 4## components - an anti-symmetric tensor built from the direct product of two...
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    I Deriving AdS Poincare Coordinates from Global Coordinates

    Zee (sort of) shows Poincare coordinates as coming from solving $$(T^2 - X^2) + (W^2 - Y^2) = 1$$ for $$W^- W^+ = (W - Y)(W + Y) = 1 + (X^2 - T^2)$$ and then setting ##X = x/w##, ##T = t/w## to find $$W^- W^+ = 1 + \tfrac{x^2}{w^2} - \tfrac{t^2}{w^2} = \tfrac{1}{w}[w + \tfrac{1}{w}(x^2 - t^2)]$$...
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    I What is SR transformarion for bispinor?

    A four vector ##x^{\mu}## transforms under a Lorentz transformation as ##x^{\mu} \to x'^{\mu} = (e^{-\frac{i}{2}\omega_{\rho \sigma} J^{\rho \sigma}})^{\mu} \, _{\nu} x^{\nu}## where ##J^{\rho \sigma}## generate the vector representation of the Lorentz algebra, ##(J^{\rho \sigma})^{\mu} \...
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