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230103
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location Greece
age 74
visits member for 3 years, 7 months
seen 2 hours ago

Retired experimental particle physicist.

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


10h
comment Dark matter a medium for light propagation
@user1247 Classically there exist an electric field and a magnetic field, and they need a source. The electromagnetic manifestation is a wave propagating in space in specific loci. If I am being stubborn it is because I am defending the answer, which is a good and complete one with no need of invoking QFT . I searched "classical electricity and magnetism " by Panosfsky and Philips for "electromagnetic field" with 0 results. fisica.net/ebooks/eletricidade/…
11h
comment Dark matter a medium for light propagation
@user1247 Sorry but this board is for answering specific questions so the questioner can learn something "Is dark matter a candidate to fill void left by luminiferous ether as a medium for light travel" this is completely within the classical framework and can be negated there. Introducing QFT in a nutshell is not necessary, imo .
19h
comment Does dark energy annihilate energy?
There are no antiphotons or antigluons, they are themselves their own antiparticle. Photon photon interactions have very small probability and gluon-gluon will create more gluons or other particles. Energy is kinetic and mass energy ( E=mc**2) for all particles .
20h
comment Dark matter a medium for light propagation
@user1247 I was talking of classical fields which is the background of the question. Not of the QFT vacuum, which respects Lorenz invariance of course .
1d
comment Dark matter a medium for light propagation
@user1247 the electromagnetic field is actually a varying electric and magnetic field with energy and momentum, not permeating all space either.
1d
comment Dark matter a medium for light propagation
Dark matter may propagate sound, i.e. pressure waves of some type. In general it has been hypothesized to fit the gravitational orbits of galactic clusters, so dark matter is not something permeating all space uniformly.
1d
comment Dark matter a medium for light propagation
no. the michelson morley experiment shows that there exists nothing with the attributes of ether and special relativity has made everything consistent. what void?
1d
comment Can an experiment be designed to distinguish between actual wave interference and probability or pilot wave results?
the single particle double slit experiments show that the wave structure appears in the space probability distribution, so no two actual waves interfering. en.wikipedia.org/wiki/…
1d
comment What experiment would prove string theory?
He is active in physicsoverflow.org
1d
comment What experiment would prove string theory?
@TerryBollinger It has been done, have a look at my question and Ron Maimon's reply here physics.stackexchange.com/questions/27671/…
2d
comment If we could build a neutrino telescope, what would we see?
I think the BB model is already tested better with the gravitons, (if the BICEP2 results are confirmed by other setups). In any case, this link scienceblogs.com/startswithabang/2013/07/17/… says the task is impossible "If you want to know what you can do to win a Nobel Prize, come up with a way to detect them, and the Nobel Prize in physics will surely be yours!"
2d
comment If we could build a neutrino telescope, what would we see?
After BICEP2 the CMB date has been surpassed, as gravitational waves have given a snapshot of the inflationary period, at 10^-32 sec, while CMB is at 380000 years.en.wikipedia.org/wiki/BICEP_and_Keck_Array . Why should one go to the incredibly difficult task of detecting such cold neutrinos?
2d
answered Does an electron move in a conductor?
2d
comment Questions about electromagnetism
@DavidZ I had already translated it while you were cogitating on holding. I edited , so maybe you can open it?
2d
revised Questions about electromagnetism
added 307 characters in body; edited title
2d
answered Questions about electromagnetism
Aug
30
comment Does a high energy photon experience deceleration or direction-change when it impinge into water or something due to the change of refraction index?
since this came up to front again, I have to note that the photons are not absorbed and re-emitted. Absorption is a quantum effect for a photon. It either gives up all its energy and disappears, and if a photon is re emitted it will have a 2 pi angle to decay into, so the phases will be lost, or it scatters with the various ways photons can scatter elastically or inelastically.
Aug
29
revised Can I throw a stone through my window without breaking the glass?
added 406 characters in body
Aug
29
answered Can I throw a stone through my window without breaking the glass?
Aug
29
comment How Exactly Does Linear Regge Trajectories Imply Stability?
thanks . you mean it is a second level string theory validation, validation by embedding more limited theories that themselves are validated by data. i.e. no direct line string theory which has not already been predicted by the minor ones. :(