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From: PD on 11 Mar 2010 14:41
On Mar 11, 1:24 pm, John Polasek <jpola...(a)cfl.rr.com> wrote:
> On Wed, 10 Mar 2010 14:14:12 -0800 (PST), PD
>
> <thedraperfam...(a)gmail.com> wrote:
> >On Mar 7, 11:46 pm, klausjen...(a)nordicnet.com (Klaus Jensen) wrote:
> >> I am doing research on the "fine-structure constant".
>
> >> Can anyone please explain the physical implication of the two numbers
> >> involved, 0.08542455, 1/137.03597 and how they might be used in a
> >> practical application?
>
> >> Thank you,
>
> >> Klaus Jensen
>
> >The fine structure constant (alpha) basically tells you how strong the
> >electromagnetic interaction is, and it's called a coupling constant.
>
> It's called a coupling constant for the lack of any better term.
> It would help if you could post an equation that solidifies this
> strength criterion.

I hate writing equations in ascii and would prefer to point you to
other places where folks have labored to render them.
http://www2.slac.stanford.edu/vvc/theory/feynman.html
http://en.wikipedia.org/wiki/S-matrix
http://www.docstoc.com/docs/5616267/Feynman-Diagrams
Any number of books on quantum field theory (Bjorken & Drell,
Weinberg, etc.) will show this for QED explicitly.

>
> >Gravity has a coupling constant, much much smaller than this. The
> >strong nuclear interaction's is much bigger.
>
> >If you'd care to look up "Feynman diagrams" in wikipedia, there's
> >another way you can look at it. Between any initial state and a final
> >state, there are a number of ways the interaction can go, and in
> >general if you want to calculate how often the final state will be
> >seen if the initial state is set up, then you want to combine all
> >these ways. Some ways are simpler and some ways are more complicated.
> >These get added together just like the terms in an infinite series
> >(something you'll run into in Algebra II), and in fact the series is
> >called a "perturbative expansion". The fine structure constant appears
> >in each of those terms, and to higher and higher powers as you go --
> >(alpha) to the first power in the simplest diagram, alpha squared in
> >the next simplest diagrams, alpha cubed in the next more complicated
> >diagrams and so on.
>
> Don't you think they latched onto it because it is has a pleasingly
> small value and is quite acceptably ubiquitous, never mind that
> nobody, including Feynman, has any idea what it means, but anyway,
> what's the harm?

I really don't think that's the case. There are equivalent coupling
constants for the strong and weak nuclear interactions, which have
exactly analogous roles in those quantum field theories, and by the
way the strong coupling constant does not have a pleasingly small
value.

>
> >Physically, the way I think about it is that the fine structure gives
> >you a measure of how often a photon is radiated or absorbed from a
> >lepton.
>
> >PD
>
> John Polasek

From: John Polasek on 11 Mar 2010 19:56
On Thu, 11 Mar 2010 14:24:20 -0500, John Polasek <jpolasek(a)cfl.rr.com>
wrote:

>On Wed, 10 Mar 2010 14:14:12 -0800 (PST), PD
><thedraperfamily(a)gmail.com> wrote:
>
>>On Mar 7, 11:46�pm, klausjen...(a)nordicnet.com (Klaus Jensen) wrote:
>>> I am doing research on the "fine-structure constant".
>>>
>>> Can anyone please explain the physical implication of the two numbers
>>> involved, 0.08542455, 1/137.03597 and how they might be used in a
>>> practical application?
>>>
>>> Thank you,
>>>
>>> Klaus Jensen
>>
>>The fine structure constant (alpha) basically tells you how strong the
>>electromagnetic interaction is, and it's called a coupling constant.
>It's called a coupling constant for the lack of any better term.
>It would help if you could post an equation that solidifies this
>strength criterion.
>>Gravity has a coupling constant, much much smaller than this. The
>>strong nuclear interaction's is much bigger.

If by this you mean big G, it has units of newton*m^2/kg^2 and
therefore it is not bigger nor smaller than the dimensionless alpha.

The article quotes a truly arbitrary Feynman rule: e^2/4pi = 1/137.
Since it has no units or anything (suggestion: e could be coulombs) I
guess you just have to believe in it, like transubstantiation. It's
not physics and it's not mathematics.
I would clearly have a breakthrough if I solved the equation e^2/4pi =
1/137 for charge e, and maybe win a Nobel, but I'm just not going to
do it. Charge would come out looking pretty drab as just a funny
number-I have higher expectations for the coulomb.

>>If you'd care to look up "Feynman diagrams" in wikipedia, there's
>>another way you can look at it. Between any initial state and a final
>>state, there are a number of ways the interaction can go, and in
>>general if you want to calculate how often the final state will be
>>seen if the initial state is set up, then you want to combine all
>>these ways. Some ways are simpler and some ways are more complicated.
>>These get added together just like the terms in an infinite series
>>(something you'll run into in Algebra II), and in fact the series is
>>called a "perturbative expansion". The fine structure constant appears
>>in each of those terms, and to higher and higher powers as you go --
>>(alpha) to the first power in the simplest diagram, alpha squared in
>>the next simplest diagrams, alpha cubed in the next more complicated
>>diagrams and so on.
>Don't you think they latched onto it because it is has a pleasingly
>small value and is quite acceptably ubiquitous, never mind that
>nobody, including Feynman, has any idea what it means, but anyway,
>what's the harm?
>>
>>Physically, the way I think about it is that the fine structure gives
>>you a measure of how often a photon is radiated or absorbed from a
>>lepton.
Yah I see the alpha's at the vertices which appear to be the
probability. Why is it only .007?
>>
>>PD
John Polasek
From: BURT on 11 Mar 2010 21:26
E=mc Squared

Solve for C; the speed limit in the universe:

C=SQRT(Energy/Mass)


Mitch Raemsch
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