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Retired experimental particle physicist.

The picture is a fayum . It looks like aunts and cousins of mine :).


12h
comment Quantum hadrodynamics
Sorry, it is not my field. Check in a library the link given by user74893 . It may have references to standard texts there.
16h
comment Why do people wear black in the Middle East?
You should give a link. The dress has to be very loose. Look at my answer here with some photos physics.stackexchange.com/…
19h
comment Why do electric shocks send you flying?
I was taught when working in the lab with electricity to approach any possible live wire with the back of the hand. That is because the body goes into spasm with electricity and if the finger are around the wire the spasm closes the hand and one cannot let go. Most of the effect is spasms from the body, not the energy of electricity , imo, though I have no links
1d
comment Could a civilisation contact us by laser from 50 light years away?
@AcidJazz nothing can go faster than light. higher frequency might allow for more information but not faster.
1d
comment Kayaking against the wind is faster than with wind in my back?
You could try an experiment with a buoy with a hanging weight that has some surface.
1d
comment Kayaking against the wind is faster than with wind in my back?
on the other side of the lake to what? perpendicular to what? Is there a river flowin in or aout? The currents follow contours of the sides and bottom and one would need a topology of the lake.
1d
comment Why don't photons split up into multiple lower energy versions of themselves?
The answer by dexter kim is relevant for collinear photons One needs an odd number of collinear photons, one to carry the spin of the incoming and two to cancel each other . For the non collinear case it is not important since energy and momentum violations do not allow it.
2d
comment Upsilon full decay width? (and reference request)
There is great interplay between theory and experimental measurement to extract widths, since they are convoluted with the accuracy of the measurements. Maybe reading this will help arxiv.org/pdf/hep-ex/0308020v1.pdf
2d
comment Photons have a property from the matter they interact with?
It is a theoretical statement; is it retrievable, should be the question. The photon did disturb the cones on the retina and the information of its existence was transferred, maybe of its energy if the color was noted , but spin and polarization information is dispersed as far as perception of one photon goes. As the other answer states, light emerging from zillions of photons is a different matter.
Sep
1
comment What is Quantum Mechanics really about?
I found the pdf for the lectures, page 81 :) cds.cern.ch/record/276704/files/CERN-64-13-V-3.pdf
Sep
1
comment What is Quantum Mechanics really about?
IMO it is the way that the many body problem is solved, that any quantum mechanical calculation on measurable quantities has to face to get at numbers (except simple potential well approximations). One writes the Feynman diagrams, follows the one to one rules for vertices and propagators and ends up with an integral which will give a number to compare with measurement.
Sep
1
comment What is Quantum Mechanics really about?
I am an experimentalist. Way back in the 1960's I had the same problem as you. I was taking a field theory course following the book of Bogoliubov and became quite expert at working with creation and annihilation operators in solving exercises and quite bewildered with what that had to do with real physics. Then I went to the 1964 summer school of Physics of CERN where Veltman gave a series of lectures on how to calculate crossections using the creation and annihilation formalism, and the scales fell from my eyes :). Yes, the wavefunction formalism is underlying all those bras and kets.
Sep
1
comment Dr. Pierre-Marie Robitaille: On the Validity of Kirchhoff's Law
this might enlighten you rationalwiki.org/wiki/Pierre-Marie_Robitaille . There was a discussion here on his cosmic background radiation ideas, which really are bizarre.
Aug
31
comment What is special about quantum entanglement?
@or1426 Of course it does , it is a probabilistic theory on the observables that is different from the calculations of classical probability. But it is still all about prior mathematical correlations, imo.
Aug
31
comment What is special about quantum entanglement?
I am of the same opinion, that quantum entanglement is a shorthand way of saying "the system is described by a quantum mechanical state function which when operated upon by the operator for an observable gives the value of the observable with a calculable probability ", that is the prior knowledge. I consider all these musings on entanglement navel gazing.
Aug
30
comment Motion of electron and proton in semi infinite magnetic field?
Have a look at pa.msu.edu/courses/1997spring/PHY232/lectures/magforces/…
Aug
29
comment Is there an example of a situation where you need a continuous spectrum?
Just that the corrections are insignificant within the width of the quantum energy levels due to the smallness of the gravitational constant. the electron is bound to the proton, not the center of the earth
Aug
29
comment Why don't photons split up into multiple lower energy versions of themselves?
@DavidZ The gluons are virtual and do not have the problems of special relativity , as the answer of user3042711 points out. I almost reached the argument by my exact 0 angle but did not make the connection to gamma of SR. Maybe since it was bothering me like a sore tooth I would have done it ( if Lubos had not thrown the abelian group argument in)
Aug
29
comment Why don't photons split up into multiple lower energy versions of themselves?
It is the argument I am using also but +1 for the colinear case;
Aug
28
comment Why don't photons split up into multiple lower energy versions of themselves?
@HC_ the electron is an elementary particle, also the photon. quarks are also elementary but their strong interaction keeps them always bound in appropriate to the symmetry group bunches. Only in cosmological setups they are supposed due to the highe energies to be free in a soup of quark gluon plasma.