Photon Emission

[watcher]

i was thinking about this for quite sometime. . . is there an exact physical mechanism that describes how an electron emits/radiates/shoots-out a photon from itself as it jumps down to its lower orbital?

[CraigD]

The physical mechanism that describes how electrons absorb and emit photons is described by QED. A key to understanding the photon-electron interactions described in QED is that not only “actual” photons of EM radiation are involved, but also virtual photons that “carry” the forces between charged particles.

 

QED calculations are complicated – strictly speaking, infinitely so – so for the most simple case, a single non-ionized hydrogen atom in a gas, the photon emitted or absorbed has an energy, which corresponds exactly to its frequency, is closely approximated by the difference in energy between its start and end orbital. Even in this most simple case, calculations based on atomic orbital electron transitions are only approximations, because the proton involved in the interaction with the electron that produces the behavior is not an elementary particle, like the electron is, but caries its charge in 3 quarks. More complicated cases, involving atoms with more than 1 electron, multiple atoms in molecules or non-gases, and “lose” electrons in plasmas, are less well approximated using orbitals.

 

Because the quarks, electrons, and other charged elementary particles describe by quantum mechanics are elementary – meaning they aren’t composed of smaller particles – there’re no “smaller scale” physical mechanisms that explain these QM interactions.

[Rade]

Because the quarks, electrons, and other charged elementary particles describe by quantum mechanics are elementary – meaning they aren’t composed of smaller particles – there’re no “smaller scale” physical mechanisms that explain these QM interactions.

There are many different preon models...e.g., QM structure smaller than quarks.   See for example the Rishon model papers published in top journals of physics:

• Harari, H. (1979). "A Schematic Model of Quarks and Leptons". Physics Letters B 86 (1): 83–86. Bibcode:1979PhLB...86...83H. doi:10.1016/0370-2693(79)90626-9.
• Shupe, M. A. (1979). "A Composite Model of Leptons and Quarks". Physics Letters B 86 (1): 87–92. Bibcode:1979PhLB...86...87S. doi:10.1016/0370-2693(79)90627-0.
• Zenczykowski, P. (2008). "The Harari–Shupe preon model and nonrelativistic quantum phase space". Physics Letters B 660 (5): 567–572. arXiv:0803.0223. Bibcode:2008PhLB..660..567Z. doi:10.1016/j.physletb.2008.01.045.

[watcher]

Because the quarks, electrons, and other charged elementary particles describe by quantum mechanics are elementary – meaning they aren’t composed of smaller particles – there’re no “smaller scale” physical mechanisms that explain these QM interactions.

thanks. so nobody knows how energy exchange works. we just assume it happens. i thought i was mssing something.

Edited November 28, 2014 by watcher

[watcher]

 

There are many different preon models...e.g., QM structure smaller than quarks.   See for example the Rishon model papers published in top journals of physics:

• Harari, H. (1979). "A Schematic Model of Quarks and Leptons". Physics Letters B 86 (1): 83–86. Bibcode:1979PhLB...86...83H. doi:10.1016/0370-2693(79)90626-9.
• Shupe, M. A. (1979). "A Composite Model of Leptons and Quarks". Physics Letters B 86 (1): 87–92. Bibcode:1979PhLB...86...87S. doi:10.1016/0370-2693(79)90627-0.
• Zenczykowski, P. (2008). "The Harari–Shupe preon model and nonrelativistic quantum phase space". Physics Letters B 660 (5): 567–572. arXiv:0803.0223. Bibcode:2008PhLB..660..567Z. doi:10.1016/j.physletb.2008.01.045.

 

if we could further breakdown these elementary particles, will it hopefully explains energy exchanges?

 

is it possible that the mechanism for energy exchange is thru resonance frequency of the system.

that it is vibrational energy that is being transferred?

Edited November 28, 2014 by watcher

[CraigD]

Because the quarks, electrons, and other charged elementary particles describe by quantum mechanics are elementary – meaning they aren’t composed of smaller particles – there’re no “smaller scale” physical mechanisms that explain these QM interactions

thanks. so nobody knows how energy exchange works. we just assume it happens. i thought i was mssing something.

I didn’t mean to give the impression that nobody knows how electrons emit photons, or that their dosing so is an untested assumption.

 

We understand that changes in the speed of an electron produce a photon with the energy equal and opposite to the change in kinetic energy of the electron.

 

It’s simpler to understand this for free electrons not in atomic orbitals. Such radiation is known as bremsstrahlung or “braking radiation”, Photons due to bremsstrahlung can have any energy (and thus any frequency, which in the visible EM spectrum range, corresponds to color) from zero to the total initial kinetic energy of the electron.

 

This has been experimentally verified with very high certainty.

 

I’ve a suspicion you’re searching for mechanism that explain quantum mechanical interaction in a make intuitive sense, Watcher. The conventional wisdom is that such searches are futile, because our intuition is based on observations of large ensembles of particles, which can be broken down into smaller ensembles, and, ultimately, into elementary particles such as electrons. At these very small scales, however, particles cease to follow our intuitive idea of how bodies should behave. This disagreement between theory and observed data and intuitive expectation is commonly called “quantum weirdness”.

[watcher]

sorry that's not really what i meant. i know that qm is the most succesful theory ever so it must be well understood.

 

perhaps what i meant is that qm now is like newtons universal law of gravitation then, whereas the "general physical law were derived from empirical observations by what Isaac Newton called induction." so that they can calculate without having an idea what gravity is. the same way we can make predictions in qm without a full understanding of what eneegy exchange is

Edited November 28, 2014 by watcher

[CraigD]

sorry that's not really what i meant. i know that qm is the most succesful theory ever so it must be well understood.

In 1965, Feynman famously said:

I think I can safely say that nobody understands quantum mechanics.

The use of QM is well understood, but I’m unsure that it’s well understood on an intuitive level, even 50 years after Feynman’s famous quip.

 

I’m not sure it isn’t, by a few physicists and/or philosophers. Though I’m certainly no physicist, and am a philosopher in little more than the sense of loving wisdom, but after nearly 40 years of amateur acquaintance with it, have lots of profound-feeling intuitions about quantum mechanics. The deepest one is that its “there is no smaller scale mechanisms” quality is not due to lack of progress in the field, but to a genuine, fundamental feature of reality, having to do with permitting the observable universe to consist of a finite quantity of data.

 

perhaps what i meant is that qm now is like newtons universal law of gravitation then, whereas the "general physical law were derived from empirical observations by what Isaac Newton called induction." so that they can calculate without having an idea what gravity is. the same way we can make predictions in qm without a full understanding of what eneegy exchange is

Another famous quote along these lines is commonly attributed to Feynman (incorrectly, as it was actually written in 1989 by David Mermin):

If I were forced to sum up in one sentence what the Copenhagen interpretation says to me, it would be "Shut up and calculate!"

 

Though it refers to QM calculations of phenomena like interference and entanglement, not Newtonian physics calculations of gravitational phenomena.

 

I think it’s accurate to say that QM, though more accurate than Newtonian physics in explaining small scale phenomena is less complete in describing phenomena on all scales, because as yet it hasn’t successfully included an explanation of gravity.

 

General Relativity gives a more – perhaps, in all but extreme situation such as within the event horizon of a black hole, perfectly – accurate explanation of gravity than Newton’s law, but GR isn’t a part of QM. While QM follows the laws of Special Relativity, neither SR nor GR follow the principles of QM.

 

Some famous physics popularizers, such as Michio Kaku, have called out the success of SR, GR, and QM, and the fundamentally disagreement between the Relativity and quantum theories as one of the greatest outstanding high-level problems of theoretical physics.

[sanctus]

Wrt:

 

sorry that's not really what i meant. i know that qm is the most succesful theory ever so it must be well understood.

 

There is another quote I heard (don't know who to attribute to, though):

Whoever tells you he/she understood QM on an intuitive level is lying.

 

And I agree completely with it, there just so many anti-intuitive things in QM. I mean how can you imagine a particle travelling from A to B trying ALL possible paths and only takes a specific one (the most likely one) if you measure it? There were experiments which show this to be the case. The mathematics of it is quite easy, but to say that is intuitive...

[watcher]

Wrt:

 

 

There is another quote I heard (don't know who to attribute to, though):

Whoever tells you he/she understood QM on an intuitive level is lying.

 

And I agree completely with it, there just so many anti-intuitive things in QM. I mean how can you imagine a particle travelling from A to B trying ALL possible paths and only takes a specific one (the most likely one) if you measure it? There were experiments which show this to be the case. The mathematics of it is quite easy, but to say that is intuitive...

einstein said every dick and harry think he knows quanta. but they are mistaken.

bohr said, quanta are not particles and they are not waves. these are classical objects borrowed just to make qm intelligible.

 

imo, incoherent interpretation like these taking all possible paths and future photon going back in time

is also a part of our fundamental  misunderstanding about the subject.

 

for instance, hans tetrode conclusion upon pondering energy exchange said :

"When I see light from a star 100 light years away,

not only do I know that the light was emitted 100 years ago but also a group of atoms in the star knew that the light would enter my eye 100 years later,

before I even existed!"

 

since energy exchange is between to  electrons ( with opposite spin) is mediated by a fixed amount of energy (photon) .. ..

and since it is fixed or in quantum, it cannot diminished by distance or dissipated in time.

so regardless how far or how long light traveled, the amount of energy emitted is always equal to energy received.

the inverse square law does not apply to individual photons but only to the average number of photons emitted.

to me this meant that fundamental quantum energy exchange is instantaneous and will resolved tetrode's and feynman's dilemma.

only as a wave, light seems to have a finite velocity of c.

Edited November 30, 2014 by watcher

[watcher]

In 1965, Feynman famously said:

 

I think I can safely say that nobody understands quantum mechanics.

The use of QM is well understood, but I’m unsure that it’s well understood on an intuitive level, even 50 years after Feynman’s famous quip.

 

I’m not sure it isn’t, by a few physicists and/or philosophers. Though I’m certainly no physicist, and am a philosopher in little more than the sense of loving wisdom, but after nearly 40 years of amateur acquaintance with it, have lots of profound-feeling intuitions about quantum mechanics. The deepest one is that its “there is no smaller scale mechanisms” quality is not due to lack of progress in the field, but to a genuine, fundamental feature of reality, having to do with permitting the observable universe to consist of a finite quantity of data.

 

 

can we really say it's finite when there is a planck of an uncertainty in our measurement?

i think i appears finite because it is the smallest measurement our measuring stick (light) can make.

but i intuit that it is further infinitely divisible , it's just that we came to the limits of  our physical "realms".

 

 

 

  Another famous quote along these lines is commonly attributed to Feynman (incorrectly, as it was actually written in 1989 by David Mermin):

If I were forced to sum up in one sentence what the Copenhagen interpretation says to me, it would be "Shut up and calculate!"

 

Though it refers to QM calculations of phenomena like interference and entanglement, not Newtonian physics calculations of gravitational phenomena.

 

I think it’s accurate to say that QM, though more accurate than Newtonian physics in explaining small scale phenomena is less complete in describing phenomena on all scales, because as yet it hasn’t successfully included an explanation of gravity.

 

General Relativity gives a more – perhaps, in all but extreme situation such as within the event horizon of a black hole, perfectly – accurate explanation of gravity than Newton’s law, but GR isn’t a part of QM. While QM follows the laws of Special Relativity, neither SR nor GR follow the principles of QM.

 

Some famous physics popularizers, such as Michio Kaku, have called out the success of SR, GR, and QM, and the fundamentally disagreement between the Relativity and quantum theories as one of the greatest outstanding high-level problems of theoretical physics.

 

 

i feel that we really don't have t invent new physics to reconcile the two. as if the answer is just right in out nose. and that the problem lies only within our own lack of full understanding.  i wonder what could have happened if science embrace fully  de broigle wave theory of matter instead of going the particle way.  but its all moot now, we spent billions for particle accelerators already and we cant just set it aside.

 

 

ps. if the discussion drifted towards philosophy, pls feel free to transfer the thread to the appropriate sub forum. tnx

[rodin]

I think Andrew Ancel Gray makes a good case that there is no such thing as a photon

 

http://www.scienceforums.com/topic/11645-7-reasons-to-abandon-quantum-mechanics-and-embrace-this-new-theory/

Edited April 25, 2015 by rodin