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Natural Science Forum / Physics / Research / September 2007



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Feynman Propagator

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T.M.Tlas@gmail.com - 05 Sep 2007 17:13 GMT
Hello everyone,

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.

T
sweetser@alum.mit.edu - 07 Sep 2007 14:14 GMT
Hello T:

I cannot answer the specific question, but I recall a relevant comment
in a particle field theory book by Kaku.  To find the propagator, all
one needs to do is to invert the field equations.  That cannot be done
for a gauge theory until you choose the gauge.

Weinberg wrote a few papers in the 1960's that were suppose to be an
arbitrary spin approach, but I found those articles too technical to
understand.  All I wanted was the propagator for a massless spin 2
field (if anyone knows it, feel free to send it to me off the group at
sweetser at alum mit edu).

doug
Arnold Neumaier - 08 Sep 2007 01:13 GMT
sweetser@alum.mit.edu schrieb:
> Hello T:
>
[quoted text clipped - 6 lines]
> arbitrary spin approach, but I found those articles too technical to
> understand.  

Weinberg's papers on 'Feynman rules for any spin' and some related
questions are
   Phys.Rev. 133 (1964), B1318-B1322  any spin (massive)
   Phys.Rev. 134 (1964), B882-B896    any spin II (massless)
   Phys.Rev. 135 (1964), B1049-B1056  grav. mass = inertial mass
   Phys.Rev. 138 (1965), B988-B1002   derivation of Einstein
   Phys.Rev. 140 (1965), B516-B524    infrared gravitons
   Phys.Rev. 181 (1969), 1893-1899    any spin III (general reps.)
A perhaps more understandable version of part of the material is in
   D.N. Williams,
   The Dirac Algebra for Any Spin,
   Unpublished Manuscript (2003)
   http://www-personal.umich.edu/~williams/papers/diracalgebra.pdf

http://ptp.ipap.jp/link?PTP/51/249/
constructs covariant propagators and complete vertices for spin J bosons
with conserved currents for all J.

Arnold Neumaier
Uncle Al - 08 Sep 2007 18:56 GMT
> sweetser@alum.mit.edu schrieb:
> > Hello T:
[quoted text clipped - 25 lines]
> constructs covariant propagators and complete vertices for spin J bosons
> with conserved currents for all J.

Phys.Rev. 135 (1964), B1049-B1056  grav. mass = inertial mass
http://prola.aps.org/abstract/PR/v135/i4B/pB1049_1
Lorentz invariance is assumed

Affine and teleparallel gravitation theories wholly contain GR.  They
disjointly additionally allow for an anisotropic chiral vacuum
background that violates Lorentz invariance.  Chemically identical
maximally opposite parity mass distributions would

  1) violate the Equivalence Principle.  They would locally vacuum
free fall along divergent (diastereotopic) minimum action trajectories
(left or right shoes on a vacuum left foot);
  2) violate conservation of angular momentum.  Noether's theorem
requires isotropic vacuum for coupling symmetry to conserved
observable.
  3) evince measurable divergences.

Any substance grown as single crystals in enantiomorphic space groups
P3(1)21 and P3(2)21 (the quartz group) qualifies.  Benzil
(Ph-CO-CO-Ph, mp=95 C) allows a rapid, simple, remarkably sensitive
parity calorimetry experiment performed in off-the-shelf hardware.  It
allows separation of parity-divergent chiral vacuum insertion energies
(time-independent) and Equivalence Principle parity violation
(dependent upon time of day and geographic orientation of the test
masses, as with an Eotvos experiment).  It is quantitative.  A
non-null output allows prediction of the corresponding parity Eotvos
experiment non-zero net output performed with alpha-quartz.

http://www.mazepath.com/uncleal/lajos.htm#a2
scheduled for Christmas 2007

Signature

Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/lajos.htm#a2

Hendrik van Hees - 08 Sep 2007 01:13 GMT
You find this and a whole bunch of other functions nicely discussed in

Pauli Lectures on Physics, Vol. 6, Selected Topics in Field
Quantization, Dover Publications

a masterpiece textbook series (especially the volume on
non-relativistich quantum mechanics!), although a bit oldfashioned
(especially this volume 6), but one clearly sees the didactic heritage
of Pauli's great teacher, Arnold Sommerfeld, whose lecture notes are
the best source for classical physics. It's a textbook style which
sadly seems to be lost nowadays!

> Hello everyone,
>
[quoted text clipped - 4 lines]
>
> T

Signature

Hendrik van Hees                        Texas A&M University
Phone:  +1 979/845-1411                 Cyclotron Institute, MS-3366
Fax:    +1 979/845-1899                 College Station, TX 77843-3366
http://theory.gsi.de/~vanhees/faq       mailto:hees@comp.tamu.edu

T.M.Tlas@gmail.com - 09 Sep 2007 02:25 GMT
Thank you all for the references but it seems most of you have
misunderstood what i asked for. It wasn't the feynman propagator for
arbitrary spin, rather the *position representation* of the feynman
propagator of the usual massive scalar field (spin 0) in a spacetime
of *arbitrary dimension* whose metric has *arbitrary signature* (so
for example the answer would be some function of the spacetime
interval that depends on the dimension of the spacetime D and on the
type of the metric put on it, for example D=8, and signature ++++
+---).

Note that essentially the answer amounts to taking the Fourier
transform of the simple function 1/(p^2 - m^2 + i epsilon) with
respect to p (p is of course a D-dimensional vector and p^2 is defined
of course with the given metric). I expect it to be some sort of a
bessel function as this is the answer for the 4d and 3d cases in the
riemannian and lorentzian metric signatures.

Dear Hendrik, does this book has the explicit formulae relevant?

Regards,
T

> You find this and a whole bunch of other functions nicely discussed in
>
[quoted text clipped - 9 lines]
>
> T.M.T...@gmail.com wrote:

> > Hello everyone,
>
[quoted text clipped - 9 lines]
> Phone:  +1 979/845-1411                 Cyclotron Institute, MS-3366
> Fax:    +1 979/845-1899                 College Station, TX 77843-3366http://theory.gsi.de/~vanhees/faq      mailto:h...@comp.tamu.edu
Hendrik van Hees - 09 Sep 2007 15:15 GMT
> Dear Hendrik, does this book has the explicit formulae relevant?

Yes, but only for the physical case of d=4.

Signature

Hendrik van Hees                        Texas A&M University
Phone:  +1 979/845-1411                 Cyclotron Institute, MS-3366
Fax:    +1 979/845-1899                 College Station, TX 77843-3366
http://theory.gsi.de/~vanhees/faq       mailto:hees@comp.tamu.edu

 
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