Can we observe Feynman-Stueckelberg interpretation?
dud...@gmail.com
soup, particles should be able to choose between future and past light
cones to leave it.
Such going backward in time particles were considered as Feynman-
Stueckelberg interpretation - they should have negative energy, so
that going forward in time particles from this scattering would get
more energy. If the scattering was in an accelerator, this particle
would most probably hit some detector BEFORE the scattering.
It agrees also from the perspective of our perception of time - this
particle (now with positive energy) was produced by this detector
before the scattering and goes straight into the scattering point,
increasing the energy.
Can such situation take place in reality?
If yes the amount of such particles should be rather small - could we
detect that detectors produced more particles than usually just before
the scattering?
Accelerators are full of extremely precise detectors, but they are
specialized in detecting absorbed not produced particles. Such
production could start some chemical processes, but they could be too
slow and generally could be interpreted as some artifacts.
Observe that such effect would create very nontrivial causality
relation - we could use that physics should stabilize such causality
loops to create extremely powerful computers:
http://groups.google.com/group/sci.physics.foundations/browse_thread/thread/a236ada29c944ebb
-------- Moderator's note ---------------------------------
The above description of the Feynman-Stueckelberg trick is wrong.
Indeed it contradicts its whole purpose, namely to give an interpretation
for the quantum-field modes of negative frequency in relativistic QFTs. The
correct interpretation is to interpret these modes as anti-particles with
positive energies going in the opposite direction of momentum, leading to
a creation operator for the corresponding physical state in the fundamental
field operator.
The whole point of relativistic QFT is that there are no states with negative
energy (if the vacuum energy is normalized to 0 as usual). So particles with
the behavior described in the above posting do not exist within the standard
model of elementary particles which is based on local, microcausal QFTs with
a stable ground (vacuum) state.
dud...@gmail.com
Interpretation, antimatter is identical to matter but moves backward
in time".
http://arxiv.org/html/physics/9812021v2
I think it's simplification: particles are some localized in 3
dimensions and long in the last one solutions of the field - they
don't go forward/backward in time but just are some paths between two
points in 4D spacetime.
We have our subjective perception of direction of time, but it is the
result of the boundary conditions with relatively small entropy (big
bang). And so we choose the sign of energy (like psi(t)=exp(-itH)psi
(0)).
What is less subjective is the causality: reason-result chains. And
CPT conservation suggests that such relations should be possible in
both time directions.
--------------- Moderator's comment --------------------------
The comment to the original posting still holds: There's nothing going
backward in time in the Feynman-Stueckelberg trick of local
QFT. To the contrary, this interpretation of negative-frequency modes
avoids entities running "backwards" in time. By construction, QFT is
causal!
Oh No
>-------- Moderator's note ---------------------------------
>
>The above description of the Feynman-Stueckelberg trick is wrong.
>Indeed it contradicts its whole purpose, namely to give an
>interpretation for the quantum-field modes of negative frequency in
>relativistic QFTs. The correct interpretation is to interpret these
>modes as anti-particles with positive energies going in the opposite
>direction of momentum, leading to a creation operator for the
>corresponding physical state in the fundamental field operator.
I don't entirely agree with this. Clearly what we observe are positive
energy anti-particles, but the Feynman-Stueckelberg interpretation is
that these are really negative energy particles going backwards in time.
Hence the creation and annihilations processes are reversed. Of course,
this is just interpretation, and makes absolutely no difference to the
experimental predictions. Certainly we don't expect to observe any
particular behaviour on account of this way of looking at qft.
Regards
--
Charles Francis
moderator sci.physics.foundations.
charles (dot) e (dot) h (dot) francis (at) googlemail.com (remove spaces and
braces)