The magical creation of the photon.
Posted 11 December 2007 - 01:32 PM
I have two hydrogen atoms on a collision course at some low velocity. When the fields of each atom get to some point in their approach each electron jumps to a higher energy level and then as they began to separate each electron falls back to the lower energy level and creates a complete infrared waveform with a crest and trough. Could someone please elaborate on this to give us a good description of each step in this event?
Posted 11 December 2007 - 09:46 PM
Just to remind everyone, while proper spelling and grammar might help, no one here--well no one with any *manners* (and those that lack them don't last very long in most cases!)--cares if you can spell. Most folks around here have English as their second or third language, so its really unimportant...
Great thread, I couldn't even spell creation.
Now I know absolutely nothing about this topic, so I'll yield the floor to someone (with good manners!) who does...
At the Derek Zoolander Center For Children Who Can't Read Good And Wanna Learn To Do Other Stuff Good Too, we teach you that there's more to life than being really, really good looking,
Posted 12 December 2007 - 11:55 AM
and then as they began to separate each electron falls back to the lower energy level and creates a complete infrared waveform with a crest and trough. Could someone please elaborate on this to give us a good description of each step in this event?
the only thing i can think to add is that the electron will drop specifically into the third energy level of a hydrogen atom when photons in the infra-red spectrum are emitted. A small point but apparently it was significant enough for me to have to learn it for my physics exam that i put behind me about a month ago.
P.S. i have a dictionary sitting next to me and i still make plenty of spelling mistakes, making me a prime example of laziness.
Posted 12 December 2007 - 02:51 PM
Posted 13 December 2007 - 06:43 AM
the dirac equation
Dirac equation - Wikipedia, the free encyclopedia
and the free maxwell equations
Maxwell's equations - Wikipedia, the free encyclopedia
sorry I dont know how to write equations in this editor havent figured it out yet
In 1928 when dirac put his equation forward the only particles known to science were the electron proton and photon.
The free maxwell equations describe the photon which in 1927 Jordan and Pauli provided an overall scheme for describing free photons according to a quantized free field maxwell theory.
Dirac's equation seemed to describe both electron and photon.
The EM interaction describing how electrons and protons are influenced by photons was handled by diracs gauge idea
Quantum field theory - Wikipedia, the free encyclopedia
If dirac style protons and electrons interacting merely electromagnetically were the only constiuents of atoms then atoms would immediately disintegrate.
In 1932 Chadwick discoverd the neutron and it was realised there must be a strong force binding neutrons and protons together
Radioactivity was desribed in another interaction the weak force.
Many other particles have been added since then
positron neutrino muons pions kaons lambda and sigma particles
omega minus particle antiparticles quarks gluons and W and Z bosons.
The modern theory also demands transient entities called virtual pair particles to exist..
So the Standard Model is as you can see far from elegant.
As for your question on desribing the production of infrared waves from the electron this comes under QED and would involve feynmann diagrams , I have no idea how to display feynmann diagrams on this thing so I will pass it over to someone who does.
Posted 13 December 2007 - 08:48 AM
Posted 14 December 2007 - 05:45 AM
True, it would be very complicated to discuss the exact details of this type of thing, although not inconceivable. It would require a lot of numerical calculation. It isn't difficult to qualitatively describe transitions between energy eigenstates, for the fixed Coulomb potential, as discussed in, for example, the Eisberg Resnick textbook. This is simple compared with actually integrating the differential equation.
they do not describe the actual event.
Posted 15 December 2007 - 10:07 AM
Posted 15 December 2007 - 02:11 PM
I think everyone made a good effort at helping me out and I appreciate it. Those efforts have I think, illustrated my point. We do not have an understanding of the steps that produce a photon. The equations work beautifully but they do not paint (the picture is worth a thousand words). In my opinion we are missing an important piece of information about the relationship between the electron and proton. What that might be I don't know. I hope that someone somewhere will answer that question before I die.
Ok I will try a different tack,
The atom consists of the nucleus and electrtons
these electrons around the atomic nucleus can only exist at certain energy levels.
For simplicity we can call these energy levels 'Shells'
When an electron 'jumps' between 'Shells' it releases an electromagnetic wave in other words a 'photon' given by the relationship E=hv.
The link between electrons and protons is they are both fermions with half integer spin.
I hope this helps
Posted 15 December 2007 - 03:46 PM
Let me begin by filling in some of what I think are key details needed for understanding in Little Bang’s original description
Here, we need to consider what we mean by “the fields of each atom”.
I have two hydrogen atoms on a collision course at some low velocity. When the fields of each atom …
In particle physics, force fields (except for gravity) are the result of exchanges of particles in the boson family by particles in the fermion family. In this example, the bosons are photons of magnetic force, exchanged mostly between the two electrons of the hydrogen atoms, but also, to a smaller net effect, between the two protons. Protons, or more properly, their constituent quarks, are also exchanging photons of magnetic force with electrons. Because we can’t measure these photons any way but by their effect on the protons and electrons, they’re called virtual. Precisely how many and when they’re exchanged is a matter of probability, not certainty – “quantum weirdness”, but very physically real.
The major thing all this virtual photon exchanging accomplishes is changing the momentum of the most massive parts of the atoms, their protons – or more properly, their most massive constituents, which are not their quarks, but the boson exchanged by the quarks, gluons.
In the process of this, the electrons will be placed in a “higher”, which is to say, less statistically likely, ”orbit”. These orbits are due to the exchange of magnetic force photons with the quarks of their protons, and are further constrained by the quantum wave functions of the electrons. These wave functions essentially require that the circumference of the electrons’ orbits be an even multiple of their de Broglie wavelength, causing these orbits to be discrete, or “quantatized”. The electrons then return to their lower, “ground” orbits. In so doing, they emit real photons of radiation. A hydrogen atom, or a system of two hydrogen atoms, can emit only photons of various discrete frequencies. Since this example states that the atoms were colliding at a low speed, we can assume that the electrons will have been raised to orbits not much greater than their ground states, and all these photons will be fairly low energy, in the infrared range.
… get to some point in their approach each electron jumps to a higher energy level …
There’s no requirement that the hydrogen atoms separate. They can remain close together, with nearly all of the kinetic energy of their former relative motion converted to photons of infrared radiation. This is the process by which a warm hydrogen gas, and eventually, a liquid and solid, cools, and can continue until the atoms near absolute zero temperature, and their relative motion is too low to raise many electrons above their ground orbits.
… and then as they began to separate each electron falls back to the lower energy level …
The electrons just emit discrete photons of an energy exactly equal to the difference in potential energy between their higher, “excited” orbit, and their ground orbit. The wave nature of this photon is inherent in it, requiring no special timing on the part of the electron or the other particles interacting with it.
… and creates a complete infrared waveform with a crest and trough. …
If you research the details of the above, the degree of my simplification of my explanation will become apperant. In particular, you’ll see I fudged considerably with the idea of the ground state orbit of an electron, because hydrogen emits infrared photons only for transitions to it’s second-from lowest orbital and above (for example, for Paschen series transitions to its 3rd orbital).
As Qfwfq notes, actually working out the details of what I’ve outlined would be a very complicated calculation. You’d have to statistically account for a literally infinite number of discrete exchanges of virtual photons, and many other difficult details. As many physics wags have noted over since Dirac and others first described this stuff, the only simulator really adequate for these sorts of calculations is the universe itself I hope, though, I’ve left Little Bang with a different opinion than
The understand he seeks exists, I think, even if the exact mathematical mechanics of it are complex beyond practical calculation, and even approachable only by a small number of superbly educated and practiced physicists.
We do not have an understanding of the steps that produce a photon. The equations work beautifully but they do not paint (the picture is worth a thousand words). In my opinion we are missing an important piece of information about the relationship between the electron and proton. What that might be I don't know. I hope that someone somewhere will answer that question before I die.
Posted 19 December 2007 - 09:28 AM
Posted 19 December 2007 - 10:28 AM
Regardless of this being feasible or not, I agree that an understanding isn't impossible. What we don't understand is certain aspects of quantum reality itself.
Posted 19 December 2007 - 12:35 PM
Posted 19 December 2007 - 04:12 PM
Anyway, we don't NEED two hydrogen atoms to make a photon. Simply punching (accelerating) an electron will create a photon. In this case, I believe that narrative description would be as follows:
The electron is sitting in space, surrounded by a cloud of virtual particles, constantly absorbing and emitting them in accordance with the uncertainty principle ([imath] \Delta E\Delta t \approx \hbar [/imath]). When the electron is accelerated away, it will leave behind (one or more) virtual particles, which become real, and travel away as photons. Descriptions for hydrogen atoms work similarly- only is a bit more complicated due to the fact that there are more particles involved.
Is it guaranteed that all forces are carried by a particle or is there some small possibility that we are totally wrong and that they might in fact be magnetic in nature?
It might be possible that certain forces (well, at least gravity) might NOT be carried by a particle. It is,though, considered very unlikely. However, gravity can't be magnetic in nature as magnetic forces have no (observed) monopoles, while gravitational monopoles are everywhere. (anything with mass).
We have observed the particle that carries the electromagnetic force (photons), we have also observed W and Z bosons (carrying the weak force). We have not yet observed gluons, but have lots of circumstantial evidence. This suggests that if not all, most of the fundamental forces are carried by particles.
I realize that 99% of the community thinks the standard model is the only way to go so it is very hard to get anyone to entertain anything outside of it. We all know that SM has many gaps or gray areas that need improvement.
I don't think this is necessarily true- the problem with the standard model is that a. we know it isn't perfect, and b. there are absolutely no experimental faults in it. The problem isn't that it has many gaps or gray areas, but rather that it has too few!
I admit that the lack of a good "gut-level" interpretation of everything quantum (not just the standard model) is very unsettling. However, given that our intellects evolved to deal with a certain scale (not too fast, not too small), I don't think it should be a deal breaker that our intuition fails at the quantum level.
Posted 19 December 2007 - 09:04 PM
Posted 19 December 2007 - 10:32 PM
What particle carries the force that holds the electron to the proton?
More photons. A proton is surrounded by virtual photons that it is emitting and absorbing (just like an electron). When we put an electron down in this cloud of virtual photons it interacts with them (and it has its own cloud of virtual photons which interact with the proton).
It is this mutual exchange of photons that holds the electron to the proton.