Photon Creation

[Little Bang]

You make a good point eras, I agree.

[Little Bang]

Never think you have an original idea someone else has probably already had it, Particle accelerator physics - Google Books

[Little Bang]

In an electron positron annihilation two gamma waves are emitted in exactly opposite directions. Does anyone know the mechanics of how that happens? I would think it to be an extremely important piece of information.

[Erasmus00]

In an electron positron annihilation two gamma waves are emitted in exactly opposite directions. Does anyone know the mechanics of how that happens? I would think it to be an extremely important piece of information.

 

You can understand that it has to be opposite directions from conservation of energy/momentum. If the electron+positron had 0 total momentum, the photons must have 0 total momentum.

[Little Bang]

I guess you misunderstood my query. We have two point particles that come together and change into two photons. What happens during this coming together that changes them into photons.

[Qfwfq]

First, the "exactly opposite" statement holds only in the rest frame, this is reasonable to understand (indeed, obvious) once you consider the previous point about energy-momentum conservation.

 

As to the mechanism, are you in the mood for quantum field theory or do you prefer semiclassical correspondence?

 

In the first case, it is just one way of turning around the coupling between the EM and the charged fermion fields. The coupling (or interaction) term in the lagrangian corresponds to the vertex in the Feynman diagrams. In this specific case, the vertex has one photon line and two for the charged fermion; one of these two has an arrow pointing toward the vertex, the other's arrow points away from it. Consider a diagram with two such vertices, connected by a fermionic line, so that the whole has the same two fermionic external lines and two photoni lines; the anihilation is just when the former stand for the incoming pair and the latter are the outcoming photons. If you ask why the diagram of just one vertex can't decribe the pair anihilating into a single photon, the answer is that it couldn't conserve energy-momentum, so it just doesn't happen.

 

By semiclassical correspondence, during the process the pair form a positronium, which is like a hydrogen atom but it has a postron instead of the proton. Also, it differes by not being stable, even in the lowest orbital state. Therefore the process is completed by the transition from this orbital state to plunketty clump and this radiates the two photons somewhat like other orbital transitions in ordinary atoms. Semiclassically the opposite charges are whizzzzzzzing 'round each other so the dipole they form is radiating like a tiny antenna.

[Little Bang]

So it is unlike a two car collision where I can examine the evidence leading up to the collision and the evidence after and then describe what occurred during their coming together? The Feynman diagrams describe a state before and the state after with nothing about during the collision. We could describe the starting distance between the two particles and their terminal velocity using Coulombs law but since we do not have a clue as to what a point particle is we have no idea what happens during that collision. We have all heard the term, " Book smart. ". Sometimes I think we should call ourselves, " Book stupid. ".

[Qfwfq]

The Feynman diagrams describe a state before and the state after with nothing about during the collision.

They are a computational instrument, a way to keep track of countless terms in a mathematical formalism. Fortunately, for most processes only the simplest ones are a significant contribution, otherwise you'd have to consider all possible diagrams with the same incoming and outgoing lines.

 

We have all heard the term, " Book smart. ". Sometimes I think we should call ourselves, " Book stupid. ".

Well I don't know exactly what you mean but there's no point in calling ourselves book stupid just because these things are very difficult; everybody finds them complicated and there's not much you can do about it.

 

The mathimatical formalism suggests that it's somehow just a coupling between different oscillations. Because the oscillations are quantized, they somehow have the corpuscular aspect and the coupling seems to be somehow like corpuscles of some kinds becoming ones of other kinds. It all seems to be a neither-fish-nor-fowl kind of a thing. If you want to understand it perfectly, phone God and ask Him for a better explanation. :cocktail:

[Little Bang]

Definition: " Book Stupid ", a person that has absorbed so much information about how the Universe works from text books, periodicals and books that we find it difficult to address any questions outside the information with which the mainstream has filled those items. Is Einstein's explanation of gravity sufficient, the pioneer anomaly, the rotation curve of galaxies anomaly? Our explanation of mass and charge is joke. The field of the electron and proton is a virtual particle joke. A bible thump-er is a person who claims to have all the answers and when you ask for proof they thump the bible and say, “It's here in the book.” Surly you can see the possibility that the standard model is used in somewhat the same manner. When we can explain the nuts and bolts of an electric field without the use of a particle that we can never test we will have all the answers.

[Pyrotex]

So it is unlike a two car collision where I can examine the evidence leading up to the collision and the evidence after and then describe what occurred during their coming together? ...

There is an effort going on currently to do this. But the theory and practice of it are not complete yet. It has to do with the merger of "twistor" theory and "string" theory.

 

Ever play Conway's Game of Life? It's the most famous form of Cellular Automatons. Consider an infinite plane divided into a grid of squares; each square can be "on" ("1", black) or "off" ("0", white); all squares are re-evalutated each "generation"; with a set of rules that determine the subsequent state of each square as a function of the current states of its immediate neighbors and itself.

 

Patterns of squares ("cells") with specific states, can evolve through several generations re-creating the same pattern -- only displaced by several cells. The pattern appears to "move" across the plane in a straight line. Life enthusiasts give these mobile patterns names such as Glider, Spaceship, and Turtle. Mobile patterns can collide with other mobile or stationary patterns, creating new patterns, some of which may be mobile. They have found that a Glider can collide with a static square Block, causing a momentary patch of chaos for a couple of generations, then resolving back into a Block and another Glider; but this one traveling at a right angle to the original one.

 

One can waste hours, DAYS, playing with Life. I have. :cocktail:

 

The new theory is that at the base bottom level of quantum existence, there is just bundles of something -- light? energy? tension? fields? -- and these bundles are called "twistors". Twistors do not move. They experience no space, no time. They experience only their neighboring twistors. They each have two or more "states", and the dynamics of their existence cause them to behave like a field, which can affect the states of its neighbors and vice-versa.

 

In the large, these twistors, existing somewhere near the Plank scale, make up Space. Their ability to change states, and change the states of their neighbors, give rise to Time. Space and Time become emergent phenomena that are apparent only at much greater scales.

 

[CAUTION: THE REMAINDER OF THIS POST IS A PLAUSIBLE FICTION]

 

Patterns of twistors can, like in the Game of Life, can be recurring; the same pattern can recreate itself over and over, each time looking the same, but comprising a different set of twistors. In other words, the pattern can be said to "move" with respect to the background of twistors. (Just like an ocean wave can "move" though the water molecules remain stationary.) The very simplest pattern that can do this is probably the Quark. But it is not "stable" except in the presence of other Quarks.

 

The simplest pattern that can "move" across the twistor-field without "assisance" is the photon. It's repetitive re-creation is manifested by its "wave" nature.

 

Unlike in Life, where random blotches of cells can litter the landscape like garbage (called "ash"), and interfere with the (rare) moving patterns. The twistor-field favors patterns that re-create and move. Momentary patches of "random" twistor states (ash) tend to chaotically "sparkle" about until the entire patch, or some portion of it, accidently evolves a stable pattern. Indeed, whereas in the Game of Life, the ash is stable, and moving patterns are fragile, in the realm of twistors, it appears to be the other way around.

 

Self-recreating patterns in the Game of Life do not have "properties" that "conserve". Sure, a Glider always has 5 cells "on", but the Glider itself doesn't have anything that we might call "momentum" or "energy".

 

The rules of Twistor Theory would be different, in that each "neighborhood" of twistors has its own "generations" determined by the local conditions. Not all twistors everywhere change states at the same time; there is no time. And the stable patterns of twistors (let's call them all, Quants) do conserve certain "properties" that become "manifested" or "emergent" at larger scales. The most primitive of these are Space and Time. Further up the ladder of scale, we find charge, mass, energy, momentum, and others.

 

Quants combine (as their conserved properties allow) into larger Quants, with more complicated inner dynamic structure. See the "Glider Guns" in the Game of Life for a metaphorical example of this. These inner dynamics tend to be tightly cyclical structures. A Quant with one kind of these may manifest "Mass"; say an electron. Have TWO of these cyclical structures inside, and you may get a medium heavy meson. Have THREE of these cyclical structures, and you may get a heavy meson.

 

These interior dynamic structures cannot exist on their own, without the surrounding "membrane" twistor patterns that give rise to electron-behavior or neutron-behavior.

 

Now to your question. What happens in a collision between electron and positron?

 

In the Game of Life, when two Gliders collide, you usually get a chatic patch of garbage that soon dies out, leaving some stable static objects behind (ash), like Blocks or Blinkers. Perhaps nothing is left at all.

 

In the Game of Twistors ( :rolleyes: ) the moving patterns have conserved properties. Charge is one of these, but these particles have opposite charge. Energy is one of these, and energy is never negative. What is energy? It's not "anything" at all. It's merely a numeric value we can attach to certain emergent attributes of these dynamic semi-chaotic patterns of twistors changing state in a mad frenzy. Attributes which maintain a constant "value" no matter what the current overall pattern that has formed.

 

The two particles get close, closer. Their outer membrane twistors begin to interact, causing twistors in proximity to change states differently than had the particle been alone. The recurring pattern of the membrane twistors gets corrupted. A region of semi-random patterns form between the particles as they collide. These semi-random patterns flicker and coelesce into other stable or semi-stable patterns.

 

The outer membranes of the particles, are replaced by sparkling unstable patterns, which are essentially random (ash). The internal twistor-field chaotically is "attracted" to several possible stable patterns, and flickers between them. Overall, however, at least two of the conserved attributes are maintained: momentum and energy. The emergent attribute of mass is lost as the original internal structures of the particles are destroyed. But "mass" locks up a great deal of another conserved property we call "energy". Though the mass disappears, its equivalent energy is conserved. The charges aren't so much "cancelled out" as they are disrupted and destroyed by the chaos.

 

As the twistor patterns that made up the particle membranes sparkle and flicker randomly, and disappear, the internal choas is attracted to the most probably stable pattern: two identical photons traveling in opposite direction. Nothing stands in their way as the outer twistor patterns fade away. Any twistors in an energetic state that are left behind, give up their energy to the departing photons as they separate and become two separate gamma rays.

[Qfwfq]

Definition: " Book Stupid ", a person that has absorbed so much information about how the Universe works from text books, periodicals and books that we find it difficult to address any questions outside the information with which the mainstream has filled those items.

What are we to do about this? I've addressed questions outside the mainstream, so long as I could make head or tail of what the queston is talking about.

 

Or, perhaps you mean it like one who has studied tons of stuff about organic chemistry, say, but has never heard of Андрей Рублёв and can't answer the most basic question about Orthodox Christian iconography? Even open minded folks might not be able and willing to follow the caperings of those who talk about something different and a lot of folks can't be bothered. They're under no obligation and the first question is whether they think it is worth their time. The second question is whether the proponent has dedicated as much of an effort to the mainstream and has understood it equally well. A case such as Smolin can answer yes to this, maybe that's why he's less considered a crackpot and has been getting gradually more attention.

 

Is Einstein's explanation of gravity sufficient, the pioneer anomaly, the rotation curve of galaxies anomaly? Our explanation of mass and charge is joke. The field of the electron and proton is a virtual particle joke.

Why do you think they say virtual as opposed to real? How many cosmologists are certain that we have the field equation exact? We don't have an explanation of mass and charge, we have a model that seems to fit the facts.

 

A bible thump-er is a person who claims to have all the answers and when you ask for proof they thump the bible and say, “It's here in the book.” Surly you can see the possibility that the standard model is used in somewhat the same manner.

The reason it's called the standard model is because it is exactly that: a model. A lot of folks are so enthusiastic about it that maybe some of them thump it like the Bible, it doesn't mean that's how it works. The scientific method isn't Bible thumping, lots of experiments have been done and accepted scientific knowledge is like "it really looks as if stuff works this way" but there is always room for further understanding.

 

When we can explain the nuts and bolts of an electric field without the use of a particle that we can never test we will have all the answers.

Of course we never will have all the answers.

 

A model will always have aspects that can't be directly seen, we can just see how well the facts match the expectations according to the model. A lot of people tend to be somewhat naïve and confuse the model with actual fact; many an electric engineer still thinks of those lines of flux as something that actually exists, for instance. This is no reason to say that electromagnetism is crap and it follows quite exactly from QED as a macroscopic consequence; likewise we can think the same of quantum field theory and standard model, even though anything beyond them is still quite the frontier.

[Little Bang]

I use the the term book stupid as a slap at the way physics is taught. The standard model has been taught, not as the only way to explain matter but as the most likely way, for over forty years. So for the vast majority of students the question becomes, " What can I do to prove the standard model? ", not what can I do to disprove the it. If a theory must invent untestable ideas to validate it's self then I find the theory lacking. There is a theory called the wave theory of matter which actually looks pretty good but it relies on space having some untestable quality so I must question it's validity. I've said this before, until we can explain the why and what of the proton and electron's field without untestable particles we're spitting into the wind.

[Pyrotex]

Twistor-String Theory

 

Twistor Diagrams

 

Roger Penrose's Course in Twistor Cosmology

 

Sir Roger Penrose

 

Penrose's Paper on the Twistor Programme

[Erasmus00]

I use the the term book stupid as a slap at the way physics is taught. The standard model has been taught, not as the only way to explain matter but as the most likely way, for over forty years. So for the vast majority of students the question becomes, " What can I do to prove the standard model? ", not what can I do to disprove the it.

 

When is the last time you took a physics class? When is the last time you took a course on the standard model? In short- how do you know how this material is taught? I find this "learning turns you into a mindless automaton incapable of really thinking" idea that is circulating to be just silly.

 

I've said this before, until we can explain the why and what of the proton and electron's field without untestable particles we're spitting into the wind.

 

What do you think is untestable?

[Little Bang]

Virtual particles

[Erasmus00]

Virtual particles

 

Virtual particles is a stupid name for an old concept. In some sense, every particle, observed and unobserved, is virtual. And you can observe them- take an electron (or any charged particle) and yank it. The photons that hit you observe were part of the cloud of "virtual" particles surrounding the electron.

[Qfwfq]

Virtual particles

Why do you think they call them virtual?

 

:(