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location Greece
age 75
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Retired experimental particle physicist.

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


Aug
22
comment How to produce neutrons
neutron stars are not one neutron. They are an agglomerate of zillions of neutrons.
Aug
22
comment What is meant by mass defect of a single neutron or a single proton?
mass defect is a statistical concept.
Aug
22
answered Euclidean geometry in non-inertial frame
Aug
22
answered How to produce neutrons
Aug
22
comment Why is the wave equation so pervasive?
@DanielSank yes, similar to lowest order in expansion of an even potential being the harmonic oscillator potential
Aug
22
answered Why is the wave equation so pervasive?
Aug
22
comment Bohr Model of the Hydrogen Atom - Energy Levels of the Hydrogen Atom
systems tend to the ground state, by radiating away physics.stackexchange.com/questions/201674/… . The cloud image is a representation of the probability density to find an electron at (x,y,z) when measuring it. Not an energy cloud, a probabilistic energy cloud.
Aug
22
comment Bohr Model of the Hydrogen Atom - Energy Levels of the Hydrogen Atom
equations do not tell that there is an energy cloud. Equations tell us that there exist energy levels fitted/modeled with the wavefunction. The energy operator operating on the wave function will give the energy of that level.
Aug
21
comment Uncertainty principle on a simple pendulum
The Heisenberg uncertainty principle depends on h_bar , a very small number. 6.6x10^-34 Joule seconds. The classical positions and momenta fulfill the inequality without any problem. It is at the quantum level of nano meters and smaller that the effects appear.
Aug
21
answered If electrons aren't revolving around the nucleus, why do atoms have orbital magnetic moment?
Aug
21
answered Could it be that all energy is seeking ground?
Aug
20
answered Bohr Model of the Hydrogen Atom - Energy Levels of the Hydrogen Atom
Aug
20
answered Observing a photon during flight
Aug
20
comment What causes gravity in M-Theory?
in the way that thermodynamics describes temperatures and pressures with different formulae than statistical mechanics, but both describe the same thing. To use statistical mechanics mathematics where the simple thermodynamics equations work is not very smart. To use general relativity where Newton's equations work again it is not very smart. To use for general relativity the string/m theory formalism ditto.
Aug
20
comment What causes gravity in M-Theory?
see also Lubos' answer here physics.stackexchange.com/q/44732
Aug
20
answered What causes gravity in M-Theory?
Aug
20
comment What's the difference between vacuum particle-antiparticle annhiliation and regular annihilation?
complicated loop diagrams . All these processes have very low probability of happening due to the large energies required from the gravitational field of the black hole. Photons are much easier to produce, even in complicated diagrams (from two e+ e- loops for example where the partners are eaten up)
Aug
20
comment What's the difference between vacuum particle-antiparticle annhiliation and regular annihilation?
@Alex In principle any pair creation follows the recipe, but strong interactions have the peculiarity of getting stronger with separation , which is what keeps quarks tied up in a proton. So single quarks cannot have one quark back into the black hole and the other free, because there are no free quarks. The energy that the interaction would take would be enormous ( thus becoming very improbable) and the free quark would bind up with some other antiquark left over from another pair, and make a pion . Thus one could have pairs of pions, pairs of proton antiproton etc, in
Aug
20
comment What's the difference between vacuum particle-antiparticle annhiliation and regular annihilation?
Mathematics is useful in physics in modelling and predicting experimental observations. Within Quantum Field Theory the Z is a virtual particle; when it becomes real , i.e. at an ouside leg of a feynman diagram, its lifetime is very short, decaying in mu+mu_, e+e- etc.
Aug
19
answered What's the difference between vacuum particle-antiparticle annhiliation and regular annihilation?