On Friday, January 11, 2019 at 7:19:06 PM UTC-6, Brent wrote:
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> On 1/11/2019 1:57 PM, Philip Thrift wrote:
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> On Friday, January 11, 2019 at 2:46:35 PM UTC-6, Brent wrote:
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>> On 1/11/2019 6:01 AM, John Clark wrote:
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>> On Thu, Jan 10, 2019 at 8:18 PM Brent Meeker <[email protected]> wrote:
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>> * > The fine structure constant is e^2/hbar*c. Those three values are
>>> measured independent of any Feynman diagrams*
>>>
>>
>> Absolutely correct. So if you use Feynman diagrams to predict what some
>> physical system is going to do, such as a physical system of 2 electrons
>> being hit by a photon of light with a wavelength small enough to contain
>> enough energy to prevent the electrons repulsion, then you'd better get a
>> number very close to the Fine Structure Constant. If you don't then Feynman
>> Diagrams aren't any good.
>>
>> They didn't use 12,672 Feynman Diagrams because they wanted to know what
>> the Fine Structure Constant was, they already knew what that number was
>> to many decimal places from exparament, they used 12,672 Feynman Diagrams
>> because they wanted to see if Feynman Diagrams worked. And it turned out
>> they worked spectacularly well in that situation, and that gives scientists
>> great confidence they can use Feynman Diagrams in other situations to
>> calculate what other physical systems will do that involve the
>> Electromagnetic Force.
>>
>>
>> There's always an interplay between theory and experiment. It's
>> completely analogous to Maxwell's discovery that light is EM waves. There
>> were already experimental values of the permittivity and permeability of
>> the vacuum and there were values for the speed of light. Maxwell showed
>> that his theory of EM predicted waves and using the permittivity and
>> permeability values the speed of the waves matched that of light. Now the
>> speed of light is a defined constant and so are the permittivity and
>> permeability of the vacuum. So the connecting of the three values by a
>> theory allows their values to be defined. In the case of the anomalous
>> magnetic moment of the electron, hbar and c are already defined constants.
>> So quantum field theory (for which Feynman diagrams are just a
>> calculational tool) linked them and e to g.
>>
>> Brent
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> If Feynman Diagrams (tools) are sufficient (to match experimental data)
> then Quantum Field Theory can be thrown in the wastebasket.
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>
> ?? Feynman Diagrams are just a mathematical trick for summing up terms to
> approximate the propagator of QFT.
>
> Brent
>
You just make Feynman Diagrams the fundamental elements of the theory, and
propagators derived from them.
Just like histories are made fundamental, and Hilbert Spaces are derived
from them.
https://arxiv.org/abs/1002.0589
Theories do not come from Mount Olympus.
- pt
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