# Why is it that when anti-matter and matter meet they produce energy?

I understand that the mass is being converted to energy but isn't it just an destructive interference of the properties of particles being present as waves of possibility , for example when electron is Interference with it self is it produce energy?,
because the particle are weaves in quantum mechanics .

## Answers and Replies

Dale
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Mass is not being converted to energy. One set of particles is being converted to another set of particles. Each set of particles (as a whole) conserves all of the same conserved properties, including energy, momentum, charge, spin, etc.

danielhaish and vanhees71
Mass is not being converted to energy. One set of particles is being converted to another set of particles. Each set of particles (as a whole) conserves all of the same conserved properties, including energy, momentum, charge, spin, etc.
so why do they cancel each other?

Dale
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2021 Award
so why do they cancel each other?
What do you mean by "they cancel each other"

What do you mean by "they cancel each other"
when anti matter and matter meet each other as I read in many places they cancel each other and produce energy

Dale
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when anti matter and matter meet each other as I read in many places they cancel each other and produce energy
Again, they convert from one set of particles into another set of particles that conserve all of the conserved quantities.

Energy is not produced, energy is the same before and after. Mass is not converted to energy, energy is the same before and after. Particles are not converted to energy, energy is the same before and after.

All other conserved quantities (charge, momentum, spin, etc) are also the same before and after.

Demystifier and danielhaish
Again, they convert from one set of particles into another set of particles that conserve all of the conserved quantities.

Energy is not produced, energy is the same before and after. Mass is not converted to energy, energy is the same before and after. Particles are not converted to energy, energy is the same before and after.

All other conserved quantities (charge, momentum, spin, etc) are also the same before and after.
so this video is wrong ? I am wanted to know in which source to use for learning

DrChinese
Science Advisor
Gold Member
When an electron and anti-electron (or any such pair) meet, a typical result is pairs of photons with the same conserved attributes as the input particles. Those resultant particles may in turn interact with others to form yet other particles. Total mass/energy is conserved per the equation E=mc^2 that I am sure you know.

The important point Dale is making is that there are a number of quantum attributes (besides mass/energy) that must be conserved. Charge, spin, etc. This is true at each step.

Dale
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so this video is wrong ? I am wanted to know in which source to use for learning
I didn't see anything in that video that was wrong, but it also did not say that energy was produced. In fact, it specifically said "the energy has to go somewhere" meaning that the energy was already there not that it was produced. In this case you were misunderstanding this source.

vanhees71
Science Advisor
Gold Member
2021 Award
Well, that's again a problem with careless popular-science writers. They say "a particle and an antiparticle annihilate to pure energy". That's somehow misleading, because of course particle and antiparticle annihilate to some other particles or photons. Everything has energy and you only transform energy from one to another form. E.g., an electron and positron annihilate to two photons. The total energy is unchanged in the process.

danielhaish
PeterDonis
Mentor
when anti matter and matter meet each other as I read in many places they cancel each other and produce energy

This is a sloppy use of language. Here "matter" and "antimatter" mean "particles with nonzero rest mass, and their antiparticles", and "energy" means "particles with zero rest mass, usually photons". And "cancel each other" means "a particle and its antiparticle interact to produce two photons". In this interaction, rest mass does disappear, but rest mass is not a conserved quantity anyway. Energy, as others have said, does not disappear, it just gets transferred from the particle-antiparticle pair to the photons.

danielhaish and vanhees71
Dale
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Well, that's again a problem with careless popular-science writers. They say "a particle and an antiparticle annihilate to pure energy". That's somehow misleading, because of course particle and antiparticle annihilate to some other particles or photons. Everything has energy and you only transform energy from one to another form. E.g., an electron and positron annihilate to two photons. The total energy is unchanged in the process.
I agree, but this specific video was a careful pop-science writer and he did not say that. Once that idea is in someone's mind from the bad writers it gets projected onto other good writers.

Vanadium 50 and vanhees71
thanks you all so they basically being interference to new wave which is a photon because photon charge is zero . does electron that being interference with it self also produce a photons ? for example like in the new slicks experience

Nugatory
Mentor
thanks you all so they basically being interference to new wave which is a photon because photon charge is zero .
No.
No interference, no waves. Just the interaction ##e^++e^-\rightarrow\gamma + \gamma##

danielhaish
PeterDonis
Mentor
they basically being interference to new wave

I don't know where you are getting that from. Particle-antiparticle pairs being converted to photons is not an "interference" process.

the particle are weaves in quantum mechanics

This is not correct. Quantum objects are quantum objects. They can behave like particles in some ways or like waves in some ways, but "particles are waves" is not a good way to describe them.

danielhaish
vanhees71
Science Advisor
Gold Member
2021 Award
I'm not sure whether I understand your question right, but if you mean whether an electron can just convert to a photon, the answer is no. There are a lot of conservation laws, which originate from symmetries, to be fulfilled. First of all there are the fundamental conservation laws from the spacetime symmetry of special relativity (Poincare symmetry): energy, momentum, and angular momentum. Then there are conservation laws coming from symmetries applied to describe interactions (gauge theories). These are conserved charges, among them the electric charge.

An electron cannot just convert to a photon by a lot of "vetoes" from conservation laws: energy and momentum conservation cannot be fulfilled. In addition also electric charge wouldn't be conserved too. That explains why an electron never can convert simply into a photon.

What can happen is that the electron scatters with some other particle. Then with some probability in addition to the scattering also one or even more photons can be produced. That's known as "bremsstrahlung" (which German for "braking radiation", when literally translated; this refers to the stopping of electrons in early days of cathode-tube experiments, from which X rays were produced and discovered by Röntgen 125 years ago).

Klystron, Dale and danielhaish
Dale
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thanks you all so they basically being interference to new wave which is a photon because photon charge is zero . does electron that being interference with it self also produce a photons ? for example like in the new slicks experience
I have already told you that annihilation is not interference:

https://www.physicsforums.com/threa...ert-to-with-interference.996938/#post-6426771

You have now had at least three people tell you the same thing.

vanhees71 and danielhaish