Recent content by Cinquero

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    Functional variation of Lagrangian densities

    Why do we treat a scalar field phi and its derivatives as being independent when trying to find a stationary solution for the action? Doesn't that give too general solutions? Where does the restriction that (d_mu phi) is dependent on phi come back in?
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    Introduction To Loop Quantum Gravity

    Actually, mys request for hyperlinks was in regard to: "Bibliography of Publications related to Classical Self-dual variables and Loop Quantum Gravity" :)
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    Introduction To Loop Quantum Gravity

    Thx! But could someone please add hyperlinks to the PDF output? :-)))
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    Introduction To Loop Quantum Gravity

    So Wick rotation = analytic continuation?
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    Introduction To Loop Quantum Gravity

    Is there a general theorem available for that purpose? I believe to remember that the mathematics behind that is usually quite non-obvious.
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    I-epsilon prescription and the definition of mass

    Read Zee, "QFT in a Nutshell".
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    I-epsilon prescription and the definition of mass

    I do not doubt that this limit exists if taking the limit _after_ integration. But that limit is just not the same as taking it inside the integral. So in practice we are calculating something very different than we wanted to calculate in the first place. I guess this is similar to the fact...
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    I-epsilon prescription and the definition of mass

    Well, I know the theory of residues. But that doesn't solve the problem that we calculate a divergent integral. As far as I have understood, we can use residues to calculate integrals which are otherwise hard to solve. It is a nice method to calculate convergent integrals. Nothing more. If it...
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    I-epsilon prescription and the definition of mass

    I'd rather say it is an unmathematical trick because we make a divergent quantity convergent... effectively resulting in something we didn't have in the first place. To make "my" problem more explicit: couldn't we just use other prescriptions and end up with different results? What is the...
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    I-epsilon prescription and the definition of mass

    In order to use the path integral formulation for the derivation of the Feynman propagator, we need to introduce a slightly complex mass. Problem: how do we interpret the circumstance that we cannot interchange integration and taking the epsilon limes? Is the parameter m in the free...
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    Mathematica Proper mathematical treatments anywhere?

    Of course. I was just somewhat confused by the fact that Amazon lists this book under Peskin, but not Schroeder... P&S: they do the same thing as Zee does: they calculate things on a lattice and then take the continuum limes. It would be no problem for me to accept that as a rule of operation...
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    Mathematica Proper mathematical treatments anywhere?

    Who are P & S?
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    Mathematica Proper mathematical treatments anywhere?

    I'm looking for proper mathematical treatments of: 1.) Formal (non-relativistic) scattering theory: construction of Moller operators from operator-valued Green's functions. How are these Green's functions defined? What's their exact use and interpretation? Why are there two of them? 2.)...
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    Is local gauge invariance limiting pQCD to a specific energy regime?

    Yes. And in general you need short wavelengths for high resolution... (form factors...)
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    Is local gauge invariance limiting pQCD to a specific energy regime?

    I rather thought of the point-like characterization of the electron in space.
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