I'm not really confusing the two, but the idea is so imprecisely put
it probably seems as though I do. The Dirac equation has both positive
and negative energy solutions. The Dirac solution to the negative
energy solutions was that they are all present as an unobservable
"Dirac sea". If you pop a particle out of the sea, the resulting hole
has positive mass, and opposite charge - what we conventionally call
antimatter. The problem is that this idea only works for fermions,
obeying the Pauli exclusion principle. Feynman's solution goes one
better, and talks about particles travelling backwards in time, which
also works for bosons.

What I was speculating was what impact embedding the Dirac equation
into a curved spacetime might have. Might it lead to a net imbalance
between matter and antimatter, or even just an imbalance between
positive and negative energy solutions. I don't know - I haven't done
the maths. It also wouldn't surprise me if someone has done the maths in
the 75 years since the Dirac equation was written down, and found it
doesn't work. 


On Wed, Oct 05, 2005 at 08:11:16PM -0700, George Levy wrote:
> Russell Standish wrote:
> >  Incidently, here's my own theory on the origin of matter. (Special)
> >  relativistic quantum mechanics delivers the prediction of matter
> >  being in perfect balance with antimatter - this is well known from
> >  Dirac's work in the 1930s. However, if spacetime had a nonzero
> >  curvature, is this not likely to bias the balance between matter
> >  and antimatter, giving rise to the net presence of matter in our
> >  universe. It strikes me that "mass curves spacetime" is the wrong
> >  way of looking at General Relativity - causation should be seen the
> >  other way - curved spacetime  generates mass. As I mentioned above,
> >  it is not surprising that spacetime is curved, what is surpising is
> >  that it is so nearly flat.
> > 
> >
> Russell, you are confusing antimatter with negative matter/energy. 
> According to convention  antimatter has inverted electrical charge and 
> therefore when the amount of matter and antimatter are in equal amount, 
> the net charge is zero. Antimatter, however, has positive mass 
> corresponding to positive energy in the sense of E=mc^2 . Consequently, 
> antimatter as well as matter give space a positive curvature.
> Negative matter/energy however are different. If negative matter/energy 
> could exist they would give space a negative curvature. Negative 
> matter/energy may be identical to dark energy.
> George Levy

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