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348179
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location Greece
age 75
visits member for 4 years, 7 months
seen 7 hours ago

Retired experimental particle physicist.

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


10h
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.
12h
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.
20h
answered What are the characteristics of light entering a disk spinning at near $c$?
1d
comment Motion of electron and proton in semi infinite magnetic field?
Have a look at pa.msu.edu/courses/1997spring/PHY232/lectures/magforces/…
2d
answered Are the particle-antiparticle pairs produced in vacuum virtual particles, and can they interact with normal particles?
2d
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
2d
answered Is there an example of a situation where you need a continuous spectrum?
2d
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)
2d
revised Why don't photons split up into multiple lower energy versions of themselves?
edit after comment and new answer
2d
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.
Aug
28
comment Why don't photons split up into multiple lower energy versions of themselves?
@HritikNarayan Sorry I will repost
Aug
28
revised Why don't photons split up into multiple lower energy versions of themselves?
clarification after comments
Aug
28
revised Why don't photons split up into multiple lower energy versions of themselves?
added 1633 characters in body
Aug
28
comment Why don't photons split up into multiple lower energy versions of themselves?
back soon. Going swimming the only costless pleasure left in Greece.
Aug
28
comment Why don't photons split up into multiple lower energy versions of themselves?
@LubošMotl But Lubos a photon in all frames has a momentum as it is moving with velocity c, thus in the rest frame of the two split photons they each have a velocity c going at an angle with the incoming momentum but adding up to zero, whereas the incoming is not zero as it has velocity c. Even collinearly, because the splits would have to be equal and opposite collinearly, adding to 0 momentum whereas the incoming still moves with c
Aug
28
comment Why don't photons split up into multiple lower energy versions of themselves?
@LubošMotl I was too lazy to think through. In my last comment yes, it shows that the energy is violated.
Aug
28
comment Why don't photons split up into multiple lower energy versions of themselves?
If it split into two photons it would have two fourvectors and these added up would have a four vector with an invariant mass. A center of mass could be assigned to them . In that center of mass the added energies and the added momenta could not add up to the original photon energy and momentum, because the original photons four vector has zero invariant mass. The momentum would be zero but the energy not. (The pio splits into two photons for example but has a mass to supply the energy).
Aug
28
answered Why don't photons split up into multiple lower energy versions of themselves?
Aug
28
answered Children of entangled particles