The discussion revolves around the quantum field theory (QFT) perspective on forces, particularly focusing on how two masses attract each other, the nature of action (instantaneous or non-local), and the conservation of momentum and energy. The conversation touches on both gravitational and electromagnetic interactions, including the role of virtual photons in these processes.
Participants express varying viewpoints on the nature of forces in QFT, particularly regarding gravity and electromagnetic interactions. There is no consensus on the specifics of how these forces operate or the implications of QFT for understanding them.
Participants highlight the complexity of the interactions and the limitations of current understanding, particularly in relation to gravity and the interpretation of forces in QFT. Some assumptions about the nature of interactions and the role of virtual particles remain unresolved.
Gerenuk said:According to QFT, how do two masses attract?
Is the action instantaneous? How is momentum/energy conserved? Is the action non-local?
Gerenuk said:According to QFT, how do two masses attract?
Yes, I did ask about gravity. But it would also be interesting to know how the Coulomb force acts through photons. At some point I will dive into QFT, but for know I was hoping to get a rough answer about what happens when two charges interaction. I mean where/when are there photons? How is momentum conserved?jtbell said:Since you said "masses", are you asking specifically about gravity? There is no generally accepted QFT for gravity yet, as far as I know, so this is still an open question.
Look at the Hamiltonian of QED. It has three terms, one for the electron, one for the EM field, and an interaction term that is like [itex]\mathbf{A} \cdot \mathbf{J}[/itex]. The virtual photons that exchange energy between the field and the matter live in the interaction term.Gerenuk said:... now I was hoping to get a rough answer about what happens when two charges interaction. I mean where/when are there photons? How is momentum conserved?
jtbell said:Since you said "masses", are you asking specifically about gravity? There is no generally accepted QFT for gravity yet, as far as I know, so this is still an open question.
Gerenuk said:Yes, I did ask about gravity. But it would also be interesting to know how the Coulomb force acts through photons. At some point I will dive into QFT, but for know I was hoping to get a rough answer about what happens when two charges interaction. I mean where/when are there photons? How is momentum conserved?