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243165
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location Greece
age 75
visits member for 4 years, 5 months
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Retired experimental particle physicist.

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


Jun
26
comment How many human cells will get affected at the prick of a pin?
a cosmic muon traversing the human body is like an infinitely thin needle for the order of magnitude of the cell.
Jun
26
comment In a CMCS 2-body system, why does the speed of the particles after collision stay the same?
It is the definition of "elastic " after all. If the kinetic energies of the particles change ( deformation for a classical example) it is called inelastic.
Jun
26
revised How is quantum mechanics compatible with the speed of light limit?
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Jun
26
answered How is quantum mechanics compatible with the speed of light limit?
Jun
26
comment How many human cells will get affected at the prick of a pin?
it is a biology question
Jun
26
comment Why doesn't atmospheric pressure crush thick walled structures?
The area cannot but be the same, by the definition, only P and F are variable.
Jun
25
answered Why can microphone be much smaller than wavelength of sound?
Jun
25
comment Heisenberg uncertainty principle clarification
Have a look at youtube.com/v/…
Jun
24
comment Why doesn't atmospheric pressure crush thick walled structures?
Your atmospheric pressure guarantees that the forces balance . That is what atmospheric pressure means, no matter how thin the material. After all you can imagine a box, no material, and if there is no wind there is no motion inside outside. When a wall intervenes it transfers the forces with its rigidity structure, and as long as the inside and outside pressure is equal nothing happens.
Jun
24
comment Can we have physical quantities which have magnitude and direction but are not vectors?
@Mew see additon above. Physical quantities with amplitude and direction can be measured but do not follow simple vector algebra as the tensor has nine components.
Jun
24
revised Can we have physical quantities which have magnitude and direction but are not vectors?
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Jun
24
answered Can we have physical quantities which have magnitude and direction but are not vectors?
Jun
24
answered Why do we need $2^\text{nd}$ quantization of the Dirac equation
Jun
23
answered Pair production by collision
Jun
23
comment What's the significance of neutrino oscillations?
That is why string theory is fascinating me, because the groups emerge from the mathematics naturally, and the data can be slotted in. The same reason gives rise to the fascination with strings because supersummetry appears mathematically in a set of theories. Supesymmetry was invoked to solve infinity problems with the calculations of the standard model and in some string theories is is there mathematically. Ad hoc mathematical models, though correct, if they cannot fit the measured group structures are just irrelevant. That should be 1963, I had started with F centers in graduate school
Jun
23
comment What's the significance of neutrino oscillations?
Much work is going on to find a theory of everything, gravity included, that is where the theoretical focus is. The standard model is taken pragmatically, as a data repository. If a new theory has the group structures and symmetries from that of the standard model then the known data have a possibility to be slotted into a greater theory. If not, the new theory is just mathematics. The group structure SU(3)xSU(2)xU(1) is an experimental observation. As well as the weak SU(3). It was an amazing continuous revelation for me, as I started doing particle physics in 1961 and followed the whole.
Jun
22
comment Does the many worlds interpretation eliminate the spooky action at a distance paradox?
Does the mathematical equation of the orbit of the moon have an objective reality other than it models the position of the moon? Same is true for the wavefunction: it is a mathematical function modeling very well the probability locus of finding an electron around a proton . I am an experimentalist and am not into interpretations. I use Quantum mechanics with its postulates raw :)
Jun
22
comment What's the significance of neutrino oscillations?
A bit like new editions of windows, example 8.1 . When changes are radical then they go to 10. We do not bother to write small changes in the SM with a different name.
Jun
22
comment What's the significance of neutrino oscillations?
There are many quantum mechanical solutions that have nothing to do with elementary particles. The standard model is a phenomenological depository in mathematical form of a great mass of measurements in the laboratories. It is not a theory in the sense that it generates the data, it is a model, a description of the data. When there are new measurements that do not have a niche in the lagrangian, a niche is provided and called beyond the standard model. We have not managed to find a niche for the antimatter matter asymmetry, it requires a radical change, but neutrino oscilations are easy to fit
Jun
22
answered Does the many worlds interpretation eliminate the spooky action at a distance paradox?