On Aug 18, 2009, at 12:23 PM, Roarty, Francis X wrote:
Horace,
QED supporters
What QED supporters?
don't like
I don't think it is a matter of taste or value judgement. It's about
precision in communication.
when I refer to vacuum fluctuations
which are also known as virtual particles but yet they do use virtual
photons in their theories.
The Casimir force is about virtual photons according to all I've
read. It has nothing to do with particle pair creation, which by
comparison is extremely rare.
I went to Wikipedia to see if there is any
defined frequency spectrum for virtual particles but they indicated
that
if the particle
This is a good example of the problem with imprecise communication.
When you say particle people think in terms of electrons, protons,
quarks, etc. These things do have wavelengths, but the concept of a
zero point field spectrum for them is uncommon to say the least.
Virtual photons, OTOH, have both a particle and wave characteristics
just like hadrons, leptons, etc, but their ubiquitous and dense
nature, as well as their very wave-like nature, lends itself to
discussion of the energy spectrum of the zero point field.
Technically, virtual photons can be called "vacuum fluctuations".
However, I think they are actually more the *cause* of vacuum pair
production, as they provide the virtual pair creation energy. In any
case, the zero point field (ZPF) consists of a huge isotropic energy
flow of virtual photons having a cubic energy distribution. I think
it is appropriate to call the ZPF a field because it consists of the
messenger particles (now an appropriate use of "particle" due to the
implied Feynman diagram concepts) which comprise the electromagnetic
field, at least the near field.
last long enough to actually be detected it is no longer
virtual!
Again, that is a reference to particle pair production. Virtual
particle pairs are limited to their Heisenberg lifetime. To survive
longer they must be given enough energy to create their mass.
What is consensus here? Is it just the infinite sea of vacuum
fluctuations they object to
No. However the Casimir force is limited to virtual photon effects,
or in other models, van der Waals force effects. It is not due to
vacuum fluctuations in general, at least I've never seen anyone
attribute the effect to that.
and they are ok with virtual particles
between matter, messengers or epo kind of thing.
Regards
Fran
One problem here is that vocabulary can mean different things
depending on the context. Sometimes when you use a word you have to
define the context in which it is used. For example, within some
contexts (GR) gravity is a result of space-time curvature, so there
is no gravity messenger particle, while within some theories, virtual
photon pressure accounts for gravity, and others gravity is a true
force, with its own messenger - the graviton. You have to be very
clear about the context in which you speak when you say something
affects "gravity", or vice versa.
Best regards,
Horace Heffner
http://www.mtaonline.net/~hheffner/
