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location Greece
age 74
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Retired experimental particle physicist.

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


Mar
15
comment Yet another double slit experiment
the second screen makes it two separate single holes with their independent diffraction pattern, if the slits are narrow enough. On the vertical screen there will be spots uncorelated, the same as would be found on the second screen if one closed off sequentially each slit. hyperphysics.phy-astr.gsu.edu/hbase/phyopt/sinslit.html
Mar
15
comment Timing of photon emission by electron in bound state
In nuclear physics one can have emission of massive particles and the lifetimes will again be described by the half life. The QM theoretical models used are various, as the shell model. The corresponding bound states of the nuclear levels again will require particular study ( before and after the decay)
Mar
15
comment Timing of photon emission by electron in bound state
Well, the electrons are described by the orbitals. To ask "where the electron is during the emission of a photon" in terms of orbitals needs the full mathematical treatment, as sketched in the answers of the other question.
Mar
15
comment Timing of photon emission by electron in bound state
In the case of the photon, yes the averages would work, though for time the half life is used to describe a decay time, as in the link.
Mar
15
revised Timing of photon emission by electron in bound state
added 165 characters in body
Mar
15
answered Timing of photon emission by electron in bound state
Mar
15
comment Is there any theoretical limit to the distance at which particles can remain entangled?
if it has been answered you should check the answer you like best
Mar
14
comment What are the “generations of matter”?
Have a look at the table of the standard model en.wikipedia.org/wiki/… . the first three columns are the families we have discovered experimentally. the first column/generation is what builds our everyday world to first order. the second and third columns are sequentially heavier and only observed in elementary particle interactions.
Mar
14
comment In theory, could gravitational waves be used to make a “gravity laser”?
@Ruslan well gravitons enter the picture in the case of stimulated emission and gravitons come with quantized gravity. I would not know what would be "too small" on a gravitational set up. Maybe you are right for the case of the free gravitational laser .
Mar
14
comment How is decoherence due to the environment compatible with the Copenhagen interpretation?
@JohnDavis There cannot be measurement without some interaction . How can there be a record? There are interactions never recorded by a human , but mathematics allows us to extrapolate , using them as probes. Collapse is a term that describes an instance ( a measurement) that will build up the probabilistic distribution predicted by the solutions of S equation for the specific boundary conditions
Mar
14
answered In theory, could gravitational waves be used to make a “gravity laser”?
Mar
14
answered What is to be considered a “body” in physics?
Mar
14
comment What would happen to me if I was in the LHC while it was running?
@Michael Energy has been fed to these circulating protons by synchronized magnetic fields. They can only slow down by impact in the geometry of the ring as they are in vacuum. Maybe one could design a complicated system of slowly absorbing magnetic energy but it would be very complicated and extra waste in energy . It is like asking "why not slow down a ferromagnetic bullet magnetically"
Mar
13
comment Helicity angle of electron in $B^0 \rightarrow K^{*0} \gamma$, with $\gamma \rightarrow e^+ e^-$?
this may help geant4.web.cern.ch/geant4/G4UsersDocuments/UsersGuides/… "polar angle of electron or positron"
Mar
13
comment Helicity angle of electron in $B^0 \rightarrow K^{*0} \gamma$, with $\gamma \rightarrow e^+ e^-$?
remember that pair production needs an extra field, a virtual photon usually. see answers. physics.stackexchange.com/questions/121629/… . you can go to the two electrons rest frame then because the nucleus balances the momentum
Mar
13
comment Is it not impossible to see a single atom using visible light?
@SirElderberry thanks, I added it at the end
Mar
13
revised Is it not impossible to see a single atom using visible light?
addition after comment
Mar
13
answered Is it not impossible to see a single atom using visible light?
Mar
13
answered Is there a way to calculate the photoelectric effect in QED via a Feynman diagram?
Mar
13
revised Why the CMB has not been dispersed so far?
clarification