In my limited understanding, antimatter just means the particles have the opposite charge of normal matter. All other attributes are not part of the definition of antimatter.

[–] Bipta@kbin.social -2 points 11 months ago (1 children)

Charge isn't the right word, although I'm not sure what the right word is. Otherwise you've got it right.

[–] LanternEverywhere@kbin.social 10 points 11 months ago (2 children)

No, charge is the right word. But i was wrong about charge being the only difference, apparently antimatter's "parity" and "time" are also opposite of normal matter. Whatever that means.

https://en.m.wikipedia.org/wiki/Antimatter

[–] magoosh@feddit.nl 5 points 11 months ago

The word is charge-parity. All physical systems (at least I'm quantum physics, I cant speak for other fields) are symmetric (nothing changes) if you change C(harge), P(arity) and T(ime reversal) at the same time. This is called CPT symmetry, see https://en.m.wikipedia.org/wiki/CPT_symmetry

As antimatter can be described as normal matter going back in time (see the other comment), it means antimatter can also be described as normal matter transformed under the C and P operators. If T(particle) = antiparticle and CPT(particle) = particle then CP(particle) = antiparticle also.

And the reason you can reverse time is because most of the equations are quadratic: they have a positive and negative solution, one describes particles moving forward in time, the other solution describes antiparticles going backward in time.

NB: in quantum field theory it gets slightly more complicated, lets leave that as homework ;)

[–] redcalcium@lemmy.institute 1 points 11 months ago (1 children)

The Feynman–Stueckelberg interpretation states that antimatter and antiparticles are regular particles traveling backward in time.[18]

So just like in Tenet?

[–] LanternEverywhere@kbin.social 0 points 11 months ago

What... How...

EDIT

i asked chatgpt if antimatter travels backwards in time, and this was the reply:

Some physicists have proposed that antimatter is actually matter moving backwards in time, based on a mathematical equivalence that emerges from quantum field theory. This idea was first suggested by Richard Feynman, who wondered if all electrons could be the same electron bouncing back and forth in time. However, this is not a widely accepted interpretation, and there is no experimental evidence to support it. In fact, most physicists do not believe that antimatter is really moving backwards in time, because it is not clear what that would mean physically.

One way to test this idea is to see how antimatter responds to gravity. If antimatter falls upwards instead of downwards, that would imply that it has a negative mass and a negative energy, which could be interpreted as moving backwards in time. However, a recent experiment at CERN has confirmed for the first time that atoms of antimatter fall downwards, just like normal matter2. This means that antimatter and matter have the same gravitational mass and the same sign of energy. However, this does not rule out the possibility that antimatter and matter might fall at different rates, which would still indicate a difference in their behavior under gravity.

So, to answer your question, antimatter does not travel backwards in time, at least not in any obvious or observable way. It behaves very similarly to normal matter, except for having opposite charges and other quantum numbers. The mystery of why antimatter and matter did not cancel each other out completely in the early universe remains unsolved, and requires further investigation and experimentation

[–] stebo02@sopuli.xyz 2 points 11 months ago

Duh. Negative mass doesn't exist. Antiparticles just have an opposite charge.