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243165
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location Greece
age 75
visits member for 4 years, 5 months
seen 1 min ago

Retired experimental particle physicist.

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


16h
comment Why do particles and antiparticles annihilate?
please look at physics.stackexchange.com/questions/190463/… where I have recently answered the same question
20h
comment A confusion regarding a paragraph in The Feynman Lectures
I have the impression that one should add a little weight on the left pan to get it started to lift the right pan, as we look at the page. If we take a bit off the left the right will sink , not lift. It is probably a confusion between left and right.
22h
comment How is quantum superposition different from mixed state?
particle A from particle N will control whether the superposition of the individual wave functions is entangled/coherent or not. If it is coherent, it is called mixed. If it is incoherent it is just a superposition of independent wavefunctions which is the classical limit.
22h
comment How is quantum superposition different from mixed state?
In my view a pure state is a state with a single wave function solution of the boundary conditions. This is feasible with few particles entering the equation . From then on one has to use approximations. One type of approximation is to assume all the external interactions to the system under consideration can be replaced by a potential . Then again one can have a pure solution, to approximate the situation. Mixed solutions come when one takes individual wave functions representing the particles and approximates the solution of the total state with the density matrix. Here the "distance" of
23h
comment In atomic bomb tests under ground, where does the volume of the rocks go?
The point to stress is the "vapor turned to liquid lava" . Lava cools to a very dense state, much denser than the original soil. This will have the smallest volume for the matter in the hole, and that is why cavities that turn into craters can form.
23h
revised How is quantum superposition different from mixed state?
clarification after comment by OP
1d
comment How is quantum superposition different from mixed state?
@user36790 above was for your question. I edited my answer and changed it because it was confusing the issues
1d
revised How is quantum superposition different from mixed state?
corrected mistake
1d
comment How is quantum superposition different from mixed state?
have a look en.wikipedia.org/wiki/Phase_%28waves%29 . The wave function gets its name because it has mainly sinusoidal expressions.
1d
answered Do the interference terms disappear really after decoherence?
1d
answered Is it possible for two events happen at the exact same time?
2d
revised Why doesn't light vibrate in-situ?
bad spell checker replacement
2d
comment Can you depict the electron's electromagetic field?
the electromagnetic field of radiation is relatively simple en.wikipedia.org/wiki/File:Electromagneticwave3Dfromside.gif
2d
answered Why doesn't light vibrate in-situ?
Jun
26
awarded  Enlightened
Jun
26
awarded  Nice Answer
Jun
26
comment Does photon have size measurement because of its particle nature
@danielAzuelos Photons are quantum mechanical entities. They are not waves of energy as classical EM waves. They are described by a probability which depends on a wave function squared, i.e. has a sinusoidal form but it is a PROBABILITY to be at (x,y,z,t) and a point can describe it. The link I gave shows how these probability waves build up the classical wave which is an energy wave traveling in space.
Jun
26
comment Why doesn't atmospheric pressure crush thick walled structures?
Yes, larger area sums up to more force, except inside and outside is balanced dA in dA out to zero. Only if there is a vacuum or extra pressure as in pressure vessels the inside force is larger than the outside and if the walls are not rigid enough to withstand the force there will be an explosion as in in overblown balloon. The area is not a variable in the problem of balancing in and out forces
Jun
26
comment Does photon have size measurement because of its particle nature
@danielAzuelos Yes, the electromagnetic wave needs space , but it is composed out of zillions of elementary particles/photons see motls.blogspot.com/2011/11/…
Jun
26
revised The magnetic field of a magnetic monopole
edit needed for correctin wrong choice