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Bilge ha escrito:

Juan R.:

Bilge ha escrito:
Most people would disgree that a theory based on instantaneous
action at a distance is a better idea, since the instantaneous
part conflicts with observations.

Completely wrong!!!

Let me know when you plan to explain that statement.

To you? Newer. It is a waste of time. Just how attempt to explain to
Eric that

-c^2dt^2 = -d(ct)^2 and because x^0 = ct therefore, g_{00} = -1.
Independent of if c=1 or is not. Because if one does c=1

-1^2dt^2 = -d(1t)^2 and because x^0 = 1t therefore, g_{00} = -1 AGAIN.


As proven by many authors retarded LW potentials disagree with many
recent experimental data on Mercury forces on Hg, railguns, tokamaks
anomalies, etc. From a theoretical point of view, several authors have
proven in recent years that LW potentials are theoretically incorrect.
In the PRE article i cited above authors proved 1) LW potentials are
not complete solutions of Maxwell equations 2) The introductions of an
instantaneous action does the solutions complete.

My only criticism to that paper is the dualism concept which is solved
in my approach.

Is there some point to this superfluous digression or are you just
posting to read your own press?

The cite to paper was just for highligintg that your understanding of
relativity and instantaneous interactions is wrong

Colleague, have your hear about Wheeler/Feynmann theory of absortion?

Numbskull, have you heard about the nuclear optical model?
It has the same relevance to this thread as everything you've
posted - zero.


Nonsense!

Basically, both you and eugene suffer from the same misconceptions.
You believe the universe is _really_ galilean, deep down, and the
rest is a facade.

Another misconception! You have no idea guy!

Juan R.

Center for CANONICAL |SCIENCE)

Bilge ha escrito:

Juan R.:

Where is there a complete bound-state theory in Weinberg manual for
example?

R-QFT clearly states that only possible observables are those derived
from S-matrix, which is only valid for independent particles (remember
the cluster decomposition principle). In rigor R-QFT only deal with
free fields.

QED is only part of a quantum field theory called the standard
model. The stardard model is believed to be asymptotically free.
What makes you think that _any_ theory of E&M which is completely
independent of the weak and strong interaction at any energy
could be consistent with the unification of all three forces?
If you believe qed should require the inclusion of qcd at high
enough energies, why would you expect qed to be valid in that
regime without including qcd? If you don't think qcd is required
at any energy, how do you explain the fact that the muon magnetic
moment is correctly predicted by including qcd corrections?

Perhaps you forget i said R-QFT. I was not particularizing for QED :-).

In the

e + e = 2 photon

scattering. R-QFT only can study the wavefunction of the electrons or
the photons when are not interacting. That is when the wavefunction
factorizes |12 = |1|2.

Well, gee... Did you ever stop to consider the possibilty that
if you _define_ electrons, photons, etc., as free particles,
then the interacting particles just might not be separable into
free particle wavefunctions plus an interaction?

The only physical states in R-QFT are free fields or if you prefer free
particles. There is not bound relativistic quantum states on R-QFT.
There is not definition of interacting particles in R-QFT.

You and eugene share the same misconception. You want to define
particles on constant slices of time,

False

but you expect to obtain solutions
inconsistent with that choice. Obviously, I can choose all sorts of ways
to define t = 0. The choice is not unique. You appear to have some
underlying belief in a galilean universe. If you want to solve the
equations in a form which is manifestly covariant, use point form to write
the hamiltonian.

WRONG

Then you'll have an eigentime for the hamiltonian. Eugene
is essentially working in instant form (where all of the particles are
quantized on a single time slice) then interpreting his results as if they
had been obtained in point form, in which the causal relationship is
explicit. Unfortunately, the point form is a lot harder to work with,
which is why there's not been much done in that area compared with
instant form.

In an atom or molecule you can claim that electrons are infinitely
separated and |12 is NOT |1|2. All test of QED are for nonboundend
states for example scattering two two electrons in acellerator physics
(which is an ONE-body problem), hidrogen atoms or hidrogenic ions
He^(++). In fact, recent test of two electrons in bound states has been
a failure.

Irrelevant babbling. Apparently, you think a rebuttal consists of
inserting a bunch of irrelevant nonsense.

Curious reply. Precisely people working in bound states has proven as
one may generalize R-QFT if one want study NON-free particles. One of
generalizations is the abandonment of the Hilbert-fock space!

Yes one can obtain a Dirac equation for a single particle. What is the
corresponding equation for two particles. It cannot be derived from
field theory and equations proposed in literature /ad hoc/, for example
two-body covariant are not rigorous and not complete.

Naturally. You insist on a formalism that cannot be covariant under
what you insist upon, so what do you expect?

????

Bethe-Salpeter and others are incorrect. At one hand, one claims that
two body state is a 16 component wavefunction. At the other hand in the
interaction regime one uses propagators derived from formals series of
QED which clearly state that there is not two body wavefunction for the
two electrons.

Why you think that R-QFT states that only scattering states are
observables?

Oh. Gee... I guess you've never been on the inside of a physics
laboratory, but let's see if we can shed some light on this conundrum.
Solid state Si detectors, for example, come in a range of sizes, but just
to get a 15-order of magnitude approximation, lets say that it's circular
with a planar area of about 500 mm^2 x 1000 microns thick. Let's say we
are interested in the details of the interaction at the order of a compton
wavelength. For an electron, that's about 386 fm.

Wow! There is no way to fit my detectors aound a couple of electrons
at that distance, not to mention alignment difficulties or the kind of
naievete required to actually postulate such a scenario to motivate
even a gedanken experiment). So, first we note the detectors are a long
way from all of the excitement. Also, the particles involved in the
interaction aren't initially very close either. We might even be inclined
to treat the particles as not interacting initially or at the time they
strike the detector. Gee, what to do?

Irrelevant. This is the reason which serious people is working in a
bound state generalization of R-QFT, especially in relativistic quantum
chemistry and molecular physics, where particles are not infinitely
separated.

But wait -- By using quantum theory with a liberal helping of
common sense, we have a solution. Since we are free to choose a
representation for our states any way we choose, subject to unitarity
constraints, viola, we can break the evolution of the interaction into
pieces:

lim \exp(iH_0t')\exp(-iH(t'-t)\exp(-iH_0t)

By taking the limits for t',t to +/- \infty. repectively, we have
defined the S-matrix. Obviously, in the limit, the interaction H,
specifies all of the S-matrix elements.

The standard definition of the S-matrix is non-rigorous. It can be also
proven that the full evolution is not well-defined unless interaction H
was exactly zero. Therein the well-known claim that only free fields
are *well-defined* on R-QFT.

Still today, nobody has found the correct, consistent, and complete
relativistic equation for N-bodies (perhaps our center has already done
but are cheking details).

Nobody has found the nonrelativistic equations for N bodies either.
If you think so, write down the exact equations of motion for three
bodies interacting under a 1/r (newtonian) potential.

This triviality already suggest your weak understanding of relativistic
physics. The exact equations of motion in non-relativisitc mechanics
are very well known. There is some diffuclties on solving them due to
singular points in phase space, but modern powerfull thecniques (some
inspired in chaos theory) solve them. Divergences in the three body
problem are solved via theory of Poincaré resonances using certain
functional generalizations developed in last 50 years in the topic.

Juan R.

Center for CANONICAL |SCIENCE)

Bilge ha escrito:

Right. Juan is deliberately misconstruing the technical difficulties
to be major theoretical problems and being hypocritical about it, too.
The same technical difficulties exist in classical physics. In addition,
classical physics has severe theoretical difficulties if one tries to
create a theory of the electron, for example.

Juan R. as many other people is able to distingish technical
difficulties from fundamental flaws on some of theories currently
accepted. Some people cannot not the differences but is not my problem.

It may be really diffiicult explain the difference between "technical
difficulties" and "wrong axioms" to anyone that still believe that the
Drac equation is a wave equation.

Juan R.

Center for CANONICAL |SCIENCE)

Bilge ha escrito:

Gregory L. Hansen:

What's-his-name, author of a Dover book on classical field theory written
with the purpose of being extensible to quantum field theories, wrote
about a delayed action at a distance theory. I had trouble understanding
how a theory could be both action at a distance and delayed. Just
wondering if you know anything about that and have comments on it.

Without knowing for sure what the theory is, the opinion based on
my impression of what you described woud be ``misguided'' or ``thumb-
twiddling.'' One could ask the same question about the spatial axes,
i.e., how come everything that happens at a different time doesn't
happen in the same place?

I would think the simplest solution is to just take relativity at
face value. I mean, what's wrong with simply choosing the most obvious
explanation:

Events A and B are connected by a null ray. What is their separation
is spacetime? Well, ds^2 = 0 and d\tau^2 = 0, which makes it rather
evident that the proper distances and times separating the events are
zero. I don't see that interactions which take place over an interval
of zero to be action at a distance. Even better - all observers will
agree that the events are separated by zero proper time and proper
distance. Evidently, the description of a particle (apart from its
quantum numbers) depends the coordinates we choose to describe it.
Quantum numbers like mass, spin, charge, etc. have no coordinate
dependence, so trying to describe them as classical ``things''
doesn't work too well.


Here's a really obvious problem with the action at a distance idea.
t
|
| .C A and B are simultaneous, so they occur
| at the ``same time,'' i.e., t = 0
+----+----+ x
A B
I now perform a lorentz transform,

t
| A and C occur at the ``same time,'' i.e., t = 0
|
|
+--------+-- x
A . C
B

If interactions are instantaneous, then obviously, at most only
one of the above can be correct, in which case, the system isn't
lorentz invariant, since the two choices for t = 0 differ only
by a lorentz transform. I guess that about sums up my opinion.


Sorry to be so hard but the "obvious problem with the action at a
distance idea" is only in your head.

Juan R.

Center for CANONICAL |SCIENCE)

In article .com,
Eric Gisse wrote:

Bilge wrote:

[snip]


Yes one can obtain a Dirac equation for a single particle. What is the
corresponding equation for two particles. It cannot be derived from
field theory and equations proposed in literature /ad hoc/, for example
two-body covariant are not rigorous and not complete.

Naturally. You insist on a formalism that cannot be covariant under
what you insist upon, so what do you expect?

Is the notion of covariance fundamental to QFT also?

Lorentz covariance is not part of the definition of a quantum field
theory, but it's assumed in the standard model, and in QFTs applicable
to accelerator experiments and nuclear physics (peices of the standard
model like QED, or "the next great thing" like supersymmetry).

The sorts of QFTs used in condensed matter physics are Galilean. The
energies are generally too low for Lorentz to matter.

But probably any field theory has to be something-covariant, even if it's
not Lorentz-covariant. According to Bergmann (Introduction to the Theory
of Relativity, p15),

"Equations which do not change at all with the transformation (that is,
the terms of which are invariants) are called invariant. Equations which
remain valid because their terms, though not invariant, transform
according to identical transformation laws... are called covariant."
--
"We need to remember that when we are faced with an unstructured problem
it is we who create the model in the form of a quantitative metaphor;
there is no correct model waiting in the wings for us to call onstage." --
Thomas L. Saaty, "Mathematical Methods of Operations Research" (1988)

In article .com,
Juan R. wrote:

Bilge ha escrito:

Right. Juan is deliberately misconstruing the technical difficulties
to be major theoretical problems and being hypocritical about it, too.
The same technical difficulties exist in classical physics. In addition,
classical physics has severe theoretical difficulties if one tries to
create a theory of the electron, for example.

Juan R. as many other people is able to distingish technical
difficulties from fundamental flaws on some of theories currently
accepted. Some people cannot not the differences but is not my problem.

It may be really diffiicult explain the difference between "technical
difficulties" and "wrong axioms" to anyone that still believe that the
Drac equation is a wave equation.

Plane waves are solutions to the Dirac equation, and you think the Dirac
equation is not a wave equation?


--
"A good plan executed right now is far better than a perfect plan
executed next week."
-Gen. George S. Patton

Gregory L. Hansen ha escrito:

Plane waves are solutions to the Dirac equation, and you think the Dirac
equation is not a wave equation?

Sorry, Gregory L. Hansen i cannot waste my time discussing
undergraduate level questions.

The Dirac wave equation -which was *originally* proposed as a
relativistic generalization of Schrödinger wave equation- was
*abandoned* in R-QFT. The evolution equation in R-QFT is a
wave-funtional one, only defined for free fields -or particles-. This
is the reason that the only observable in R-QFT is the S-matrix and
observables derived from it. The Dirac equation is not longer a valid
***wavefunction*** equation as is still claimed in many "outdated"
'relativistic quantum mechanics' textbooks.

The Dirac equation of R-QFT (obtained from the QED Lagrangian) is not
the Dirac equation in the original sense of Dirac, because phi(x) there
is not a c-number wave function but a quantum operator.


Juan R.

Center for CANONICAL |SCIENCE)

Bilge wrote:

I am sorry, it seems that we have very different ideas about quantum
mechanics. I am not going to buy your interpretation,

What interpretation? What I wote above regarding the unitary
transforms you gave is mathematical fact. It's the definition
of a unitary transform. You do realize that,

\Psi|U^{-1}HU|\Psi = \Psi'|H|\Psi' = \Psi|H'|\Psi (1)

are just different ways to say the same thing, righ? If not, I
refer you to any quantum mechanics textbook, and if you need a
page number, I'll find one in schiff for you.

Thank you for your kind offer.
There are basically 3 ways to do unitary transformation in quantum
mechanics.

1. You can apply the transformation to operators of observables
e.g., H' = U^{-1}HU and keep state vectors intact

2. You can apply transformation to state vectors |\Psi' = U |\Psi
and keep operators intact

3. You can apply transformation U to observables and inverse
transformation U^{-1} to state vectors.

In cases 1. and 2. the physics is changed, i.e., expectation values
are affected by the transformation. As you correctly pointed out in
your eq. (1),
cases 1. and 2. are equivalent. They are just two different ways
to say the same thing. In the case 3. there is no change in physics:
expectation values of observables do not change. This is a trivial
change of representation.

When I was talking about unitary dressing transformation, I was
talking about case 1. Your statement about the triviality of unitary
transformations refers to the case 3. We are talking about different
things.

Eugene.