Confused about particle interactions

In summary, QFT describes the interaction between particles as being mediated by the exchange of a boson. While Feynman diagrams may suggest a single interaction between particles, in reality the interaction happens continuously and is represented by multiple photon exchanges along the particle lines. Feynman diagrams are not literal depictions of particle trajectories, but rather calculational tools that integrate over all possible paths. QFT does not provide an ontological explanation of what truly happens during the interaction, but rather predicts the outcomes of measurements.
  • #1
kelly0303
563
33
Hello! As far as I understand, in QFT the interaction between particles is mediated by the exchange of a boson. When doing calculations, one assumes that you have 2 free particles coming in, they interact at a point by exchanging a boson and then they propagate again as free particles, and this is the image the Feynman diagrams show, too. However, (say in the case of 2 electrons) the interaction doesn't take place only once. The electrons feel the effect of each other all the time, so I would imagine that a diagram reflecting this should have a photon exchange at each point along the 2 electron lines. Is this continuous interaction mathematically equivalent to just one interaction at a given point? Or how should I think about the Feynman diagrams? Thank you!
 
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  • #2
Feynman diagrams aren't spacetime diagrams that show particle trajectories. They're mnemonic devices in which each line and vertex corresponds to a factor in the calculation for the probability amplitude of the depicted process. The calculation actually integrates (in effect) over all the possible spacetime paths that the particles could take.
 
  • #3
You shouldn't take feynman diagrams too literally as depictions of what happens. They're merely calculational tools and besides that, qft only tells you what you can expect if you measure. It doesn't tell you ontologically what "really happens during the interaction".
 

Related to Confused about particle interactions

1. What are particle interactions?

Particle interactions refer to the ways in which particles, such as atoms and subatomic particles, interact with each other through various fundamental forces, such as gravity, electromagnetism, and the strong and weak nuclear forces.

2. How do particle interactions affect the behavior of matter?

Particle interactions play a crucial role in determining the behavior of matter. For example, the strong nuclear force holds the nucleus of an atom together, while the electromagnetic force governs the interactions between charged particles. These interactions ultimately determine the properties and behavior of matter.

3. What is the significance of understanding particle interactions?

Understanding particle interactions is essential for explaining the fundamental laws of physics and how the universe works. It also allows us to develop new technologies and make predictions about the behavior of matter in different conditions.

4. Are there different types of particle interactions?

Yes, there are four known fundamental forces that govern particle interactions: gravity, electromagnetism, strong nuclear force, and weak nuclear force. Each force has its own specific characteristics and effects on matter.

5. How do scientists study particle interactions?

Scientists study particle interactions through various experimental methods, such as colliding particles in particle accelerators, observing the behavior of particles in different environments, and using mathematical models and simulations to predict and understand their interactions.

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