55,990 reputation
234128
bio website
location Greece
age 74
visits member for 3 years, 11 months
seen 2 hours ago

Retired experimental particle physicist.

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


Aug
3
comment Why nuclear tests move under ground since 1964?
if you count as ecological the long term effects of radiation on humans.
Aug
2
comment Rest Mass, Where is it Stored?
I am puzzled by this statement. The rest mass of a system is always smaller than its relativistic mass. Can you give a link or a direct quote?
Aug
1
answered Can an object be infinitely small?
Aug
1
comment De-broglie wavelength in electron microscope
this link is useful for defining when relativistic effects should be taken into account hyperphysics.phy-astr.gsu.edu/hbase/relativ/rellim.html
Aug
1
comment How does optical phase modulation produce photons with different frequencies?
It will have to do with the specific boundary condition of the particular problem. One theoretically could follow the ensemble method, but it would be very cumbersome. Once one has proven that one can go from the ensemble of photons to classical fields the smart physicist uses classical fields as he/she would not use quantum mechanics to study temperature differentials macroscopically
Aug
1
answered De-broglie wavelength in electron microscope
Aug
1
comment How does optical phase modulation produce photons with different frequencies?
You will see sidebands but the value will not be ω+Ω or -. There will be an indeterminacy, similar to the one seen in the accumulation of the interference pattern when the photons go one by one. There will be a delta(ω+Ω). It is the coherent "summation" of the ensemble of photons that eliminates the delta indeterminacy and adds up to the classical accurate formulae.
Aug
1
comment Can electromagnetic radiation (i.e. photons) produce gravity?
There should be an enormous gamma ray flux to have enough effective mass to simulate dark matter. If you read the article you would see that the high energy photons come from specific points in the sky. If you read the article on darke energy you would see that it is even more complicated, because it is a postulated energy to explain the cosmological constant . It also should be uniformly spread and this is not observed: gamma rays of even higher energies would be interacting with each other giving visible signals of this. science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy
Aug
1
comment How does optical phase modulation produce photons with different frequencies?
Did you read the blog entry I linked in my answer? All classical fields emerge out of ensembles of individual photons. An individual photon is an entire elementary particle and it can only interact with the rules of quantum mechanics. In a way it is similar to how thermodynamic quantities emerge from quantum statistical mechanics. Did you watch the two slit experiment I linked to? where each individual photon follows the qm probability?
Jul
31
comment Can electromagnetic radiation (i.e. photons) produce gravity?
The answer to the last question is no, read up on dark energy en.wikipedia.org/wiki/Dark_energy . Do not confuse it with dark matter: en.wikipedia.org/wiki/Dark_matter . Gamma rays interact with matter, that is how we "see" them. They can be neither dark matter nor more so dark energy (which is supposed to permeate all space).
Jul
31
comment Can electromagnetic radiation (i.e. photons) produce gravity?
Well one can see gamma rays, which are very high energy photons. cfa.harvard.edu/~tergin/ergin.pdf
Jul
31
comment Can electromagnetic radiation (i.e. photons) produce gravity?
Dark energy is called dark because it cannot be "seen". The verb "see" includes the photon and the other elementary particles of the Standard Model.
Jul
31
answered How can the quantum state of the universe decohere
Jul
31
revised If there is no collapse of the wave-function does this mean that the many worlds interpretation of QM must be wrong?
added 390 characters in body
Jul
31
revised If there is no collapse of the wave-function does this mean that the many worlds interpretation of QM must be wrong?
added example
Jul
31
answered If there is no collapse of the wave-function does this mean that the many worlds interpretation of QM must be wrong?
Jul
30
comment Compressed Spring Dissolving in Acid
Yes, instead of one large PING if the clamps were taken out, there are proportional small pings, as each atom changes partners, from surface atoms to corrosion atoms.
Jul
30
comment How small can you be and still hear?
How about this as a recorder pimall.com/nais/microrecorder.html . And nanotechnology is getting more and more nano, so I might guess nano meters.
Jul
30
answered Compressed Spring Dissolving in Acid
Jul
30
comment Do asteroids create sonic boom while entering the atmosphere?
It is a qualitative answer, not a quantitative one, that is why it is a comment and not an answer. It is not a simple problem and it is not in my field. Have a look at en.wikipedia.org/wiki/… .