In quantum field theory (QFT), the interaction between particles, such as electrons and positrons, is described by the exchange of virtual particles. In the case of electrons and positrons, their interaction can be understood through the exchange of virtual photons.
When two electrons or two positrons repel each other, they do so by exchanging virtual photons. This repulsion occurs because the electrons or positrons interact through the electromagnetic force, which is mediated by the exchange of photons. The repulsive force arises from the exchange of virtual photons with like electric charges. The virtual photons are emitted by one particle, absorbed by the other, and their exchange contributes to the overall repulsive interaction.
On the other hand, when an electron and a positron attract each other, they also exchange virtual photons, but in this case, the virtual photons are responsible for mediating the attractive force. Electrons and positrons have opposite electric charges, so the exchange of virtual photons with opposite charges leads to an attractive force between them. The virtual photons are emitted by one particle, absorbed by the other, and their exchange contributes to the overall attractive interaction.
It's important to note that these virtual particles, such as virtual photons, are not directly observable and do not have the same properties as real particles. They are temporary fluctuations in the underlying quantum fields that mediate the interactions between particles. The exchange of virtual particles allows for the transmission of forces between particles in quantum field theory, and their nature and properties are described by the mathematical framework of the theory.