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Anonymous No. 16555158

>if a positron and an electron touch, they annihilate each other
>particles are not 0 dimensional points, they exist as a way function that permeates a big chunk of space. therefore, two particles can't touch each other because they are extended objects and we don't know where they are
>an electron and a positron can not annihilate for a while and form a bound state together called positronium where they orbit each other, even though they are as close as they can be according to quantum mechanics
>when two particles are too far away, their langrangian is the free particle lagrangian, and the interaction term magically appears when they are close to each other
I don't understand QFT

Anonymous No. 16555159

>>16555158
You indeed don’t.
>when two particles are too far away, their langrangian is the free particle lagrangian
that’s just an approximation

Anonymous No. 16555161

>>16555159
so you're saying even particles that are too far away can annihilate each other? then what's the point?

Anonymous No. 16555164

positron and electron have opposite charges thus attract eachother?

Anonymous No. 16555166

>>16555164
proton and electron have opposite charges too and yet the electron can't fall too deep into the proton because of muh quantum physics

Anonymous No. 16555167

>>16555161
I’m saying you’re a retard who doesn’t know what an approximation is. Approximations are done because the original problem cannot be solved analytically. Go read non-relativistic QM (Sakurai) before doing QFT. You describe things like an idiot who doesn’t understand the math behind anything.

Anonymous No. 16555169

>>16555158
>far away
>touch
You forget that notions of position and distance in quantum mechanics are not classically defined.

Anonymous No. 16555170

>>16555167
>why do electrons and positrons annihilate each other even though they can't touch?
>dude just learn the math
are you retarded? math explains when it happens, not why

Anonymous No. 16555171

>>16555170
Go. Learn. The. Math. Your childish interpretations mean jack shit if you don’t know the math behind things.

Anonymous No. 16555173

>>16555171
do you even know the math?

Anonymous No. 16555174

>>16555173
Yes. It’s not that hard. The basics are representation theory and the rest is the good old perturbation theory that carries on from standard QM. The way you describe things tells me you know neither.

Anonymous No. 16555175

>>16555166
you can make a neutron out of a proton and electron

Anonymous No. 16555176

>>16555174
then explain it. how does the math allow two particles to annihilate if they can't touch?

Anonymous No. 16555177

>>16555176
Representation theory tells you that. Go learn representation theory. I also don’t know what the fuck you mean by “touch”.

Anonymous No. 16555187

>>16555158
Positrons move backwards in time while electrons move forward. From the electron’s perspective, a particle-antiparticle pair interact and annihilate, converting matter into energy; from the positron’s perspective, energy condenses into matter and a particle-antiparticle pair is spontaneously produced.

Anonymous No. 16555220

>>16555158
>when two particles are too far away, their langrangian is the free particle lagrangian, and the interaction term magically appears when they are close to each other
The interaction term was always there to begin with, it's just that in the interaction picture, the fields evolve as free fields (see: https://physics.stackexchange.com/a/718199). Thusly, in the perturbative expansion of the interaction picture time-evolution operator, the interaction probability will increase with inverse distance.

Anonymous No. 16555222

>>16555220
>Thusly
SAAAAAAAAAAAAAAAAAAAAR

Anonymous No. 16555227

>>16555222
mutt education

Anonymous No. 16555230

>>16555158
Matter travels forwards in time.
Antimatter travels backwards in time.
Photons experience no passage time.
From the perspective of the electron, a particle-antiparticle pair approach and fuse, matter is converted into energy, fissioning into two photons.
From the perspective of the positron, two photons approach and fuse, energy is condensed into matter, fissioning into a particle-antiparticle pair.

Anonymous No. 16555243

>>16555158
Just do the feynman diagrams retard. Oh waitk they have been done already like 70 years ago, just read an intro QFT book and follow along retard.

Anonymous No. 16555272

>>16555227
You say “whence” too, ESL larper?