Natural Science Forum / Physics / Research / September 2007

If the expansion of the Universe is accelerating, as recent
observations indicate, and this continues, then eventually
space will be expanding at faster than light speed in a
vacuum (the so-called "Big Rip").

Can someone direct me to the original mathematics mentioned in this article:
http://www.breitbart.com/article.php?id=paUniverse_sun14_parallel_universes&show
_article=1&cat=0
The article says in part referring to apparently recent work of David
Deutsch at Oxford:

The recent report about a 50ug discrepancy in the comparison of the standard
1 Kg mass with its copies led me to wonder how such precision is attained,
50ug being 5 x 10^-9 Kg.
Can anyone describe the method of making such a comparison, and how the

It seems to me that the whole fuss about switching to euclidean time to
remove wildly oscillatory behaviour in many integrals found in QFT to be
unnecessary. For instance if we calculate <0|0>j the result is a path
integral / <0|0>[j=0]. However we cheat in our mathematics by ...

I was wondering what would happen if a roughly 10 MeV proton or
neutron was fired into a large dense target consisting of a mixture of
deuterium and tritium  - let's say several cubic metres of gas held at
high pressure but low temperature so that it is almost at the density

    Strange Aspects of the Franson Experiment
_____________________________________________________________
    This is a long post, so I will first state
its gist so that you can decide if you want to invest

This question was posed by John Zwart in the American Journal of
Physics, Vol. 70, No. 2, p. 105, February 2002 but has not been
answered since:
" According to the classical kinetic theory of gases, a rigid

    I just realized that it is *not* true that the "local realistic"
model presented in Aerts, et al., is of the type considered by Bell.
It is subtly different.      
    Therefore, there is no reason for it to

What is the difference between the intensity of a wave, and its energy?

does anybody know if there is a general formula for the position
representation for the feynman propagator of a massive scalar field in
a spacetime of arbitrary dimension and signature?
If yes i would be most grateful for a reference.

Hi Group,
There has an interesting paper appeared on the arxiv.

What do you think on this?

Classical superstrings exist in dimensions D=3,4,6,10 reflecting the
triality construction, that happens to be valid for say k=1,2,4,8 via
division algebra stuff and all that. This is well known, specially
from the work in the Brane Scan but also older papers by Evans and by

I was wondering if there is a shortest possible time to rotate about
some fixed point. Would it be, for instance, the time it takes to go
around a circle with diameter one Planck length at the speed of light?
Or is there some velocity less than light, so that the proper time to

If the amplitude of two waves are cancelled by adding them 'out-of-
phase'.  What happens to the energy?
--Daniel Tebar

Can anyone please refer me to where I could find computer models --
their graphical output, of zitterbewegung?