Recent content by iibewegung

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    Correlated multivariable gaussian random number generation

    \mathrm{prob} \propto \mathrm{e}^{-\frac{(a -x_1)^2}{2 \sigma^2}} \mathrm{e}^{-\frac{(x_1 -x_2)^2}{2 \sigma^2}} \mathrm{e}^{-\frac{(x_2 -x_3)^2}{2 \sigma^2}} \mathrm{e}^{-\frac{(x_3 -b)^2}{2 \sigma^2}} a and b are known real constants. Is there a way to generate x_1, x_2, x_3 independently...
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    Statistical Analysis in High-Energy Physics: Methods and Applications

    Hi, Could anyone tell me what type of statistical test is used to estimate the parameters of the standard model? I hear many particle physicists say, eg. "we have a 95% confidence that this quark mass falls between A and B" and what immediately comes to mind are the methods of statistical...
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    Def'n: magnetic ordering wave vectors

    Can someone give a clear definition of a ferromagnetic ordering wave vector and an antiferromagnetic ordering wave vector? I see the terms being used all over the literature (to calculate order parameters etc.) but never truly caught onto the definitions. Any help greatly appreciated-
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    [QFT] Feynman rules for self-interacting scalar field with source terms

    I'm not sure if this is the right place to post a graduate level course material, but I have a question about perturbative expansion of the 2n-point function of a scalar field theory. Homework Statement First, the question: In which space (position or momentum) is the topological distinctness...
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    Reducing autocorrelation of a time series

    Hi, Is there like some widely accepted threshold for autocorrelation time of a time series for it to be considered "uncorrelated"? I used MATLAB to generate approx. 1000 gaussian random numbers and found their autocorrelation time to be approx. 1.07... is this small enough for it to be called...
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    Langevin dynamics random force term generation algorithm

    Hi, Can anyone tell me an algorithm to generate the stationary Gaussian distribution R(t) with \langle R(t) \rangle = 0 (zero mean) \langle R(t) R(t')^{T} \rangle = A \delta(t-t') , A = 2 \gamma k_B T m (autocorrelation) ? What I just wrote is from the Wikipedia article "Langevin...
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    Thickest Physics Book: MTW Gravitation or Even Thicker?

    Just curious... Is there a single textbook (excluding freshman physics books and encyclopedias) that beats MTW Gravitation in its thickness (either ruler-measured or page number-wise)?
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    Hartree-Fock wave function for a mixture of two oppositely charged gases

    Hi, Suppose there is half-half a mixture of an electron gas and a gas of some hypothetical particle with the same mass, spin but an opposite charge (like positrons that don't decay). Would anyone be able to tell me how the Slater determinants combine in this case? The HF wave function for just...
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    Normalizer & normal subgroup related

    Sorry for wasting space... I figured it out. (wasn't reading the definition of normalizers carefully) It was one of those things that one could attach "Clearly," at the front of the statement. Unfortunately, this leads to another question... How do I delete this thread?
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    Normalizer & normal subgroup related

    [SOLVED] Normalizer & normal subgroup related Let H \subset G. Why is H a normal subgroup of its own normalizer in G?
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    When does the Hartree-Fock approximation fail?

    Thanks for the answer. actually... i decided to change the question to the one you see now (edited) on the first msg, a few minutes after writing it the first time... i was able to change the body of the msg but not the title of the thread. can this new question be answered here as well? .. or...
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    When does the Hartree-Fock approximation fail?

    Homework Statement Hi, I've read from Wikipedia that in the Hartree-Fock approximation, "Each energy eigenfunction is assumed to be describable by a single Slater determinant". My question is... if the approximation fails and the system has to be described by linear combinations of more than...
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    Unveiling the Significance of BCS Theory: Celebrating 50 Years at CERN

    I agree with what you say, but I'm not sure about Weinberg himself, or whether he meant what he was saying when he was giving this talk. (I was there) He seemed to be extremely nervous while giving the talk, especially with Philip Anderson in the audience. It seemed to me that he was invited...
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    Lowest freq mode of fixed-end linear chain oscillations

    Hi, (All oscillations I'll be talking about here are longitudinal.) For coupled oscillations of 2 masses between 3 identical springs (ends held fixed by walls), I think it was a standard textbook mechanics problem to show that the lowest-frequency mode is the symmetric one (where the masses...
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    What Are Ring Exchanges in Quantum Systems?

    Hello condensed matter gurus out there, I'm a new graduate student who's been trying to understand some sentences in a review article that reads: ----- ... One of Feynman's early successes with path integrals is often neglected, his mapping with path integrals of a quantum system onto a...
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