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236147
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location Greece
age 74
visits member for 4 years, 2 months
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Retired experimental particle physicist.

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


Jan
21
awarded  Yearling
Jan
21
answered Why does the colour wheel wrap around?
Jan
21
comment Hilbert, Gödel, and “God equations” - a 19th century lesson for 21st century physicists?
well it was in a set theory course back in 1960 so I may be paraphrasing, the professor might have proven this using G theorem.
Jan
21
answered Hilbert, Gödel, and “God equations” - a 19th century lesson for 21st century physicists?
Jan
21
comment Can universal continuity be experimentally falsified?
in this entry physics.stackexchange.com/questions/33273/… which answers your question. an experiment is mentioned arxiv.org/abs/0908.1832 which pushes the limits of lorenz invariance violation, which would happen on a discrete local spacetime
Jan
21
reviewed Reject How do I explain to a six year old why people on the other side of the Earth don't fall off?
Jan
20
awarded  Nice Answer
Jan
20
answered How do I explain to a six year old why people on the other side of the Earth don't fall off?
Jan
20
comment What force particle mediates electric fields and magnetic fields?
please add to your last paragraph that energy momentum four vector of the virtual photons, and generally all virtual particles, is not necessarily 0: virtual particles are off mass shell. Virtual particles have all the quantum numbers that characterize the name except the mass. The longitudinal spin allowed for virtual photons is due to their nonzero mass.
Jan
20
comment Geodesic for Electromagnetic forces
since user37569 who offered a link has departed and the answer deleted by Community, I am copying it as a comment: " Estakhr's Material-Geodesic Equation, meetings.aps.org/Meeting/DFD13/Session/R8.4 , which is Unification between Lorentz Force and Einstein Geodesic Equation.
Jan
20
comment Why doesn't a typical beam splitter cause a photon to decohere?
Think quantum mechanics. In a sense the final path is the collective quantum mechanical solution of elastic scattering of a photon with frequency nu through the obstacle path of mirrors and reflections. One problem, one set of boundary conditions, one energy state. It so happens that the energy states available in transparent media are such that transparency occurs :).
Jan
20
comment Why doesn't a typical beam splitter cause a photon to decohere?
I think that for a medium to be transparent to a single photon all the interactions with the photon have to be coherent otherwise transparency will be lost. I would start with the energy conservation (the photon retains its frequency as seen when ensembles of photons go through) which means the interactions with the crystal must be elastic. If in the framework of ensembles there are interference patterns then the individual photon too will have the appropriate correlations of phase. Have a look at how classical em motls.blogspot.com/2011/11/…
Jan
19
comment Do neutrinos travel faster than light in air?
@akhmeteli I will try to refresh my memory on this. reading arxiv.org/pdf/physics/0303116v1.pdf . The neutrinos are produced as flavor eigenstates and travel as mass eigenstates. page 12, "one of the masses may be zero, not known if so" so it seems you can have oscillations where one of the three masses is zero.
Jan
19
comment Do neutrinos travel faster than light in air?
@akhmeteli the flavor neutrinos have to be orthogonal in the standard model, and if there were no masses a beam with a start of a one flavor cannot after a distance have a component of another flavor. If there are masses one can posit different eigenstates of the wavefunction that allow it consistent with the SM.
Jan
19
comment Do neutrinos travel faster than light in air?
@akhmeteli our measurements always measure a flavor eigenstate, becasue we detect the corresponding flavor particle, electron, muon or tau. We experimentally found that the masses must be diferent because when we start wit a beam with only muon neutrinos, we end up in detecting also tau neutrinos. It is the ratio of detected flavors after traveling a distance that changes, and implies a difference in masses.
Jan
19
comment Do neutrinos travel faster than light in air?
@akhmeteli It is different if you are talking of wavefunctions and different if you are talking of particles that have wave functions. If you look at the table of elements particles have specific masses, not probability distributions.If you measure m1 then it is the neutrino with flavor and mass m1 you have measured, not the one with flavor and mass m2
Jan
19
comment Do neutrinos travel faster than light in air?
@akhmeteli define mix . in my math it will be something like (am_1 +bm_2)/d where a and b and d are given by whatever functional relationship nature gives and theory describes . Evebn if m_1 is 0 ,m2 remains.
Jan
19
awarded  electrons
Jan
18
comment Mosquito in a Bus
yes, with some delay during acceleration .
Jan
18
answered Mosquito in a Bus