Re: Attraction vs repulsion - why does it depend on spin?

From: Franz Heymann (notfranz.heymann_at_btopenworld.com)
Date: 03/01/05 

Date: Tue, 1 Mar 2005 20:48:03 +0000 (UTC)

<chornedsnorkack@hushmail.com> wrote in message
news:1109696430.737458.37250@o13g2000cwo.googlegroups.com...
>
> Franz Heymann wrote:
> > "Ben Rudiak-Gould" <br276deleteme@cam.ac.uk> wrote in message
> > news:d01qbq$8ib$1@gemini.csx.cam.ac.uk...
> > > Franz Heymann wrote:
> > > > <francoisbelfort@yahoo.fr> wrote in message
> > > > news:1109625494.936187.216000@l41g2000cwc.googlegroups.com...
> > > >
> > > >>(Spin 2 is already a classical property of gravity (waves) -
> > > >>independently whether gravitons exist or not.
> > > >
> > > > That last assertion cannot conceivably be true. Classically,
a
> > > > gravitational wave is a continuous process. How big a piece
of
> it
> > > > would you have to snip out on which to assign an angular
momentum
> > 2h?
> > > > And via which route did Planck's constant enter into a
classical
> > > > equation?
> > >
> > > Well, spin-N bosons are associated with rank-N tensor fields,
and
> > gravity is
> > > a rank-2 tensor field. And rank 2 tensors have a kind of 180
degree
> > symmetry
> > > to them.
> >
> > Yes.
> >
> > However, the OP specifically said "whether gravitons exist or
not"
> > If they don't exist, there is no object which could carry off the
> > angular momenta in the amounts he implied.
> >
> Well, let us approach it this way:
>
> A quantum of electromagnetic field has energy E=h*nu and spin h.
>
> It follows that a quantity of electromagnetic radiation with energy
E
> carries angular momentum L=E/nu

You serve no purpose whatever by using creative editing to hide
Planck's constant.
I notice in retrospect that you have chosen play this juvenile trick
throughout in your screed.
It is childish.

> INDEPENDENTLY of what the actual value
> of h is. It cancels out. Of course, there is a possibility of an
> electromagnetic radiation carrying no angular momentum, it is
linearly
> polarized and can be viewed as sum of opposite circularly polarized
> waves.
>
> Is it possible to use the pure Maxwell equations, without ANY
recourse
> to photon or quantization, to prove that an electromagnetic wave
> carries an angular momentum up to L=+-E/nu?

Most certainly not. Planck's constant simply does not exist as far as
classical physics is concerned.
As a matter of fact, Maxwell's equations were propounded even before
it was known that there were physical entities which carried
electrical charge in quantised units. The equations refer throughout
to continuous charge distributions.

> As for gravitations - if you analyze the pure General Relativity
> description of gravity waves without assumption of graviton, does it
> show that those waves carry up to L=+-2E/nu of angular momentum?

No. For the same reason. Classical General Relativity makes no
contact whatsoever with Quantum theory.

> Furthermore, is it possible to prove, classically, that all fields
that
> either cannot carry angular momentum at all or carry angular
momentum
> up to 2E/nu, 4E/nu et cetera must be purely attractive?

No. The attractive/repulsive details of interactions are derivable
from the vector/tensor characteristics of a field purely by the use
of a very heavy dose of quantum field theory.

> And is it
> possible to prove that fields which carry angular momentum up to
E/nu,
> 3E/nu et cetere have to be repulsive as well as attractive? And is
it
> possible to show that there cannot be any fields capable of carrying
up
> to and no more than some fractional amount of E/nu of angular
momentum?

No. The attractive/repulsive nature of interactions are derivable
from the vector/tensor characteristics of a field purely by the use of
a very heavy dose of quantum field theory. 

-- 
Franz
"The great tragedy of science -- the slaying of a beautiful hypothesis
by an ugly fact."
T.H. Huxley

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