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visits member for 4 years, 7 months
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Retired experimental particle physicist.

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


3h
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.
3h
comment Why don't photons split up into multiple lower energy versions of themselves?
@HritikNarayan Sorry I will repost
3h
revised Why don't photons split up into multiple lower energy versions of themselves?
clarification after comments
4h
revised Why don't photons split up into multiple lower energy versions of themselves?
added 1633 characters in body
7h
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.
7h
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
7h
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.
7h
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).
8h
answered Why don't photons split up into multiple lower energy versions of themselves?
10h
answered Children of entangled particles
15h
comment Can an electron go along different paths at once in a circuit
As Timaeus said in the answer you cannot have a single electron moving in a circuit. Circuits are not classical paths where an electron rolls like a ball. They are an ensemble of atoms and molecules with electrons tied up and fields set up and a single electron will either be absorbed or it will kick off another in the band to continue the journey. Only in vacuum there can be a single electron moving from A to B , or in very high energies one may see a single electron in a bubble chamber or spark chamber
18h
revised Are there theories that explain wave-particle duality?
additions after any simmilar cogitations over time
1d
answered Entropy reversal in magnets
1d
answered Is it physics that leads to development of maths or is it maths that leads to the development of physics?
1d
comment Why the Yang-Mills ansatz is able to describe every interaction we know?
Probably Newton was thinking "how can I devise a general mathematical model that will come out with the Kepler orbits".
1d
comment Why the Yang-Mills ansatz is able to describe every interaction we know?
Physics does not answer basic why questions. It describes how with certain assumptions a mathematical model from the axioms and postulates ( the correspondence of physics to mathematics "axioms" ) describes data and predicts the behavior of new data. The link can be followed up to the postulates. On the way, one can say |"I see why", but ultimately the how stops at the postulates. I suspect an explicit or implicit postulate in the theoretical models is responsible for this universality you observe. I expect probably something to do with the structure of spaces (all types of).
1d
answered Can an atoms energy levels be changed by changing the de Broglie wavelength of electrons?
1d
revised In quantum mechanics, given certain energy spectrum can one generate the corresponding potential?
expanded the answer
1d
answered In quantum mechanics, given certain energy spectrum can one generate the corresponding potential?
2d
comment Can we reconstruct 1D potentials in QM from the spectrum?
@yuggib They were looking for a mathematical model that would explain/have_as_solution the Balmer series rigorously,without the assumptions of the Bohr model. in my view this is reverse.