# How can the same virtual particle both attract and repel charged particles together?

so I've read a lot of things about QED and stuff, and I've clearly understood that charged particles are in fact "charged" because they exchange virtual photons, small packets of energy with each other, and that's ok. But I've always asked myself: how can two charged particles exchange the same virtual particle and act differently (attraction / repulsion). I've already seen the boat example of the conservation of momentum, but that makes me think that maybe charge is related to the quantum spin and orientation of the particle and direction of emission of the photon? So then why are some particles that don't have spin charged? I'm having a hard time with this. Please don't answer if your response is: "They act like this because that's how they are built", because i could say that protons are charged because that's how they are built, but we all know they are made of quarks, so I'm searching of a correlation with what I've just said.

• I wanted to add, I've also seen the explaination that it's because it could increase or decrease the electric potential energy between the particles, but all opposite and like charged prticles have positive mass, so wouldn't energy increase anyway? Commented Jun 20, 2022 at 23:57
• Also, I would like more of a concept answer than math because from what I've seen, other answers brought up maxwell's equations and stuff, but these simply describe the behavior in relation to electric charge, but they don't explain charge itself. For example i could say that I start moving because God pushes me at 1 m/s². Of course this isn't true but it serves as a good example. Commented Jun 21, 2022 at 0:09

I've clearly understood that charged particles are in fact "charged" because they exchange virtual photons, small packets of energy with each other, and that's ok.

You are confusing the natural reality which has recorded charged and neutral particles with measurements and observations, with a Quantum Field Theory model for fitting those observation in a confused manner.

In QFT the charge of the particle can be modeled as virtual photons , but not as

are in fact "charged" because they exchange virtual photons, small packets of energy with each other

but virtual particles are not small packets of energy. They are part of the mathematical model of QFT which uses Feynman diagrams for its calculations, and are called virtual because they are off mass shell and exist only in the mathematics of the calculation of particle interactions.

My answer here goes into the Feynman diagrams whose calculations will allow attraction and repulsion, and a bit about the boat analogy.

• Yes, I know that I didn't explain very well, but really what I don't understand is how two particles can exchange the photon in the same direction and, based on some unexplained reason called charge, they either attract or repel. I mean this in the real world, not in maths. In fact, if I look at the diagrams for electromagnetism, I see that when charges are like, particles seem to emit photons in a specific direction, hence the question for spin. Moreover, from what I know the Feynman diagram explain how particles react to an exchange of virtual particles, but now why. Commented Jun 21, 2022 at 13:02
• I kinda feel like QED, Maxwell's Equations etc. serve only as models for predictions, but not understanding the reasons. Commented Jun 21, 2022 at 13:17
• @BlueCrasho It is not a matter of directions, it is a matter of probability for the electrons to scatter off in a given direction with given momentum and energy . It is quantum mechanics, and if you are serious about physics you have to study its mathematics . The only way to really understand a QM theoretical model, Commented Jun 21, 2022 at 13:29