Recent content by evilcman

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    A property of meromorphic functions (?)

    All meromorphic functions can be written as the ratio of two holomorphic functions, that is true. The second statement is not true. In general a holomorphic function can't be written as a product of monomials. You will in general also have an exponential in it. And the exponential in it can...
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    A property of meromorphic functions (?)

    Is this statement true: "If two meromorphic functions have the same poles(all simple) and the same zeros(all simple), than they are proportional."? If it is true, than why? Thanks for the help...
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    Multivariable calculus question

    I have a scalar function f dependent on a few variables $x_i$, and I would like to change variables, so that y_i = \sum_j {M_{ij} x_j}, where M is an invertible matrix independent of the x_i-s, and compute: \frac{\partial f}{\partial x_i} = \frac{\partial f}{\partial \left( \sum_j...
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    Calculating Weak Interaction Processes: Four Fermion Invariants in Fermi-Theory

    In calculations of weak interaction processes in the Fermi-theory, there are some amplitudes of the form: \bar{a}(\gamma_{\alpha} + \lambda \gamma_{\alpha}\gamma_{5}) b \bar{c}(\gamma^{\alpha} + \gamma^{\alpha}\gamma_5)d where a,b,c,d are Dirac-spinors. Now, if this is a Lorentz-scalar. In that...
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    Is it possible to reproduce BBN in the lab?

    There are similarities, and there are nuclei produced in heavy ion collisions from the recombination of nucleons, but the processes are still quite different. I think one way to look at this is to think about interaction rates (number of interactions per second per particle) compared to the...
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    Running coupling of the weak interactions

    What about above the W threshold?
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    Running coupling of the weak interactions

    Well I am sure that would be the case if the weak interactions was a pure SU(2) gauge theory, but the full SM is more complicated, and I am not sure this still applies.
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    Calculating Self-Energy Correction to Electron Propagator

    If one wants, to calculate the self energy correction to the electron propagator(using the approach where one introduces a photon mass \mu to deal with IR divergences), one gets after some work an integral like this (this is from the Itzykson Zuber book equ. 7-34): \int_ 0 ^ 1 d\beta \beta...
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    H problem in statistical mechanics

    Simple regularization doesn't help either, if we sum up to state N only, then we get: -<E> = \frac{\sum E_0 exp(-\beta E_0 / n^2 )}{\sum n^2 exp(-\beta E_0 / n^2 )} < \frac{N E_0 exp(-\beta E_0)}{N^3} \to 0 which would mean that at ANY temperature, all hydrogen atoms are at a highly excited...
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    H problem in statistical mechanics

    Calculating energies with respect to the ground state just means adding E_0 to all energies, that is multiplying the partition function with exp(\beta E_0) and the sum will still diverge.
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    H problem in statistical mechanics

    Is there some kind of resolution to the Hydrogen atom problem in statistical physics, that is the fact that canonical partition function diverges for E_n = - E_0/n^2 with degeneracy n^2 since Z = \sum n^2 exp(-\beta E_0/n^2) > \sum n^2 exp(-\beta E_0) , which makes the H atom problem seem...
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    Hadron Resonance Gas: Exploring QCD Data & Thermodynamic Model

    Recently I saw a talk stating that the hadron resonance gas model, which is basically all the known hadrons put together as ideal gases, describes lattice QCD "data" really well. Like in this paper: http://arxiv.org/abs/hep-ph/0303108 In this paper Fig. 1 is what I am looking at. I tried that...
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    References for Nonlinear Sigma Model.

    A way to start can be the book Gauge Theory of Elementary Particle Physics by Cheng and Li. It has a nice chapter about Chiral Symmetry which introduces the linear Sigma model, than there is a supplementary book to it (Problems and Solutions) which has a few things about both the linear and...
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    Laplace transform of the grand canonical partition function

    Does anyone recognize this expression for the pressure: p(T,\mu) = T s^*(T,\mu) where s^* is the extreme right singularity in the Laplace transform of the grand canonical partion function. If someone knows this, I am curious in the derivation, and in what cases it is applicable. (In the...
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