Why Does Antimatter Annihilate Matter?

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Discussion Overview

The discussion revolves around the reasons behind the annihilation of antimatter and matter, exploring concepts from quantum field theory (QFT) and superstring theory. Participants delve into the implications of these interactions, including the nature of particles and the conservation of information during annihilation events.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants inquire about the fundamental reasons for antimatter's annihilation with matter, suggesting a mathematical analogy from QFT.
  • One participant explains that in QFT, antimatter can be viewed as matter traveling backward in time, leading to interactions that result in annihilation and the production of photons.
  • A different perspective from superstring theory is introduced, proposing that annihilation occurs when two strings collide, resulting in a new string that behaves like a photon.
  • Concerns are raised about the implications of annihilation, particularly regarding the loss of information, with one participant questioning if all information is destroyed in the process.
  • Another participant challenges the understanding of photons and phonons, clarifying their definitions and roles in the context of annihilation.
  • There is a debate about the emergence of heat and light from annihilation, with some participants asserting that heat is not a necessary component in this process.
  • One participant emphasizes that information is conserved in annihilation events, highlighting the conservation of energy and momentum.

Areas of Agreement / Disagreement

Participants express differing views on the implications of matter-antimatter annihilation, particularly regarding the conservation of information and the roles of photons and phonons. There is no consensus on these points, and the discussion remains unresolved.

Contextual Notes

Some claims rely on theoretical frameworks that are not universally accepted, and there are unresolved questions about the definitions and implications of terms like "heat" and "information" in the context of annihilation.

garytse86
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is there any particular reason that antimatter will annhilate matter?

This question has been bothering me for a while...

thanx
 
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garytse86 said:
is there any particular reason that antimatter will annhilate matter?

In QFT, this is mathematically as evident as the answer to the question:
"is there any particular reason that the sum of a number and its negative give 0".
If you want a more intuitive answer, in QFT (which is a relativistic theory, so treats space and time in the same way ; just as you can go to the left or the right, you can go to the future or the past), antimatter going "forward" in time is the same as matter going "backwards" in time. You can hence view the matter-anti matter interaction as matter that came from the past into the future, and at a certain point, went back into the past again. You, as an observer, who travels forward in time you will see the two entities of the same matter particle in your slice of time, one going forward (the so-called particle) and another one (which is in fact the same one) going backward in time, but which you observe as an antiparticle going forward.
When you advance your timeslice, you'll come to the point where the particle "bounced back in time", which you, going forward, interpret as an annihilation.
In order to "bounce back", the particle has to interact with something, usually the electromagnetic field (otherwise it just goes on straight forward). This interaction causes the EM field to be excited, and so the net result you observe is a particle and an antiparticle meeting, disappearing and two photons to appear. The process is called an annihilation reaction.

cheers,
Patrick.
 
thanks a lot :) that was really helpful!
 
Note that this explanation is from the point of view of a yet unproven theory...
From a superstring theory point of view, the cancellation is a result of two strings colliding, one oscillating in a way to be say an electron and the other oscillating in a way to be a positron. When they collide, they form one string. Just as two waves can be canceled out if one's crests line up with the other's troughs, the opposite crests and troughs on the oscillating strings cancel out (even in the superstring realm, something can't vibrate in two directions at once). The resulting oscillation pattern of the new string is such that it has the properties of say, a photon, in which its vibrational energy that would correspond with its mass is used up entirely by quantum fluctuations. Therefore, its massless and due to it's specific vibration pattern has the properties of what we call a photon.
 
vanesch said:
In QFT, this is mathematically as evident as the answer to the question:
"is there any particular reason that the sum of a number and its negative give 0".
If you want a more intuitive answer, in QFT (which is a relativistic theory, so treats space and time in the same way ; just as you can go to the left or the right, you can go to the future or the past), antimatter going "forward" in time is the same as matter going "backwards" in time. You can hence view the matter-anti matter interaction as matter that came from the past into the future, and at a certain point, went back into the past again. You, as an observer, who travels forward in time you will see the two entities of the same matter particle in your slice of time, one going forward (the so-called particle) and another one (which is in fact the same one) going backward in time, but which you observe as an antiparticle going forward.
When you advance your timeslice, you'll come to the point where the particle "bounced back in time", which you, going forward, interpret as an annihilation.
In order to "bounce back", the particle has to interact with something, usually the electromagnetic field (otherwise it just goes on straight forward). This interaction causes the EM field to be excited, and so the net result you observe is a particle and an antiparticle meeting, disappearing and two photons to appear. The process is called an annihilation reaction.

cheers,
Patrick.

Therefore if I am correct in saying that you just said when they collide it was as if they never existed, Only photons and phonons emerge, since one's going backwards in time and one is going forwards than all information would be destroyed, thus going against quantum theory
 
Mk said:
Therefore if I am correct in saying that you just said when they collide it was as if they never existed, Only photons and phonons emerge, since one's going backwards in time and one is going forwards than all information would be destroyed, thus going against quantum theory


That was a long sentance, if it was one... :eek:
 
Mk said:
Therefore if I am correct in saying that you just said when they collide it was as if they never existed, Only photons and phonons emerge, since one's going backwards in time and one is going forwards than all information would be destroyed, thus going against quantum theory

Photons and phonons emerge out of matter-antimatter anihilation? When did this happen?

Photon is its own antimatter. Phonon is quantized lattice vibration modes in materials. You have something weird mixing up in here that is causing a really bad diarrhea.

Zz.
 
ZapperZ said:
Photons and phonons emerge out of matter-antimatter anihilation? When did this happen?

Photon is its own antimatter. Phonon is quantized lattice vibration modes in materials.

Phonon is kind of a particle of heat right? and Photon is a particle light kind of right? When mattaer-antimater collision accurs than the product is light and heat.
 
Mk said:
Phonon is kind of a particle of heat right? and Photon is a particle light kind of right? When mattaer-antimater collision accurs than the product is light and heat.

Nope.

I have explained in my posting what a phonon is. You are confusing the IR part of the EM spectrum with lattice vibrations in a material. Phonons are a collective mode and can occur/exist only in a many-body interaction, NOT in a vacuum.

You should do background reading on what "phonons" are (a Solid State textbook would be a good start).

Zz.
 
  • #10
Well, the point was, heat and light emerge, and they don't exist after that? All information of the antimatter particle and the matter particle is lost?
 
  • #11
Mk said:
Well, the point was, heat and light emerge, and they don't exist after that? All information of the antimatter particle and the matter particle is lost?

What heat?

Heat is defined either via statistical physics (which requires a medium that we don't have in vacuum), or IR spectrum. So where is this heat?

Where exactly did you get the idea that heat is a necessary component in a pair anhilation? We could have eliminated such long-winded discussion if you could have point out where you learned this.

Zz.
 
  • #12
No, information is not lost in a matter-antimatter annihilation. Energy and momentum are conserved, even in annihilations ! :eek:
 

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