Time it takes for a particle creation/annhilation (according to QFT)?

In summary, the conversation discusses the concept of time in quantum field theory and its implications on particle interactions. The question is raised about the amount of time it takes for a high energy photon to convert into an electron and positron after striking an atomic nucleus. It is uncertain if QFT can provide an answer to this question or if it even delves into the concept of time in interactions. The conclusion is that while the interaction occurs at a single point in spacetime, the theory mainly focuses on the amplitude of the interaction at different points.
  • #1
triclon
12
0
I am curious if quantum field theory says anything about how much time it takes for an interaction, or particle creation and annihilation, to take place. For example if I have a high energy photon, and it strikes an atomic nucleus and you get pair production forming an electron and positron. In the example, I am wondering what is the amount of time it takes to go from a photon to an electron and positron. Is there a certain amount of time for that process to occur or is it "instantaneous" where one moment you have a high energy photon and a nucleus at rest, and the next you have an electron and positron? I don't know enough about QFT to say. Perhaps the theory doesn't probe into the "process" of the interaction and can't say anything about the time it takes for it to occur? Or does theory have something to say?
 
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  • #2
The interaction occurs at a single point in spacetime. However, keep in mind that you're really just saying that there's an amplitude at every point in spacetime for the interaction to take place.
 

1. How long does it take for a particle to be created or annihilated according to QFT?

The time it takes for a particle to be created or annihilated according to QFT is a complex and debated topic. The answer depends on various factors such as the energy of the particle, the type of particle, and the specific scenario. However, in general, it is believed that the creation or annihilation process happens instantaneously, as predicted by QFT. This is because QFT describes particles as excitations of quantum fields, and these fields can change their state almost instantaneously.

2. Can the creation or annihilation process be observed or measured?

No, the creation or annihilation process cannot be directly observed or measured. This is because it happens at a subatomic level, and the time scales involved are extremely small. Additionally, the process is governed by the laws of quantum mechanics, which means that the creation or annihilation of a particle can only be described in terms of probabilities.

3. Is the time it takes for particle creation or annihilation the same for all particles?

No, the time it takes for particle creation or annihilation can vary depending on the type of particle. For example, the creation or annihilation of a photon (a particle of light) may happen much faster than that of a proton. This is because photons have a lower mass and therefore interact differently with the quantum fields.

4. Can the time it takes for particle creation or annihilation be manipulated?

Currently, there is no known way to manipulate the time it takes for particle creation or annihilation according to QFT. The process is considered to be a fundamental property of the universe, and it is not possible to change it without significantly altering the laws of physics.

5. How does the time it takes for particle creation or annihilation relate to the concept of time in general relativity?

The concept of time in general relativity is different from that in QFT. In general relativity, time is considered to be relative and can be affected by factors such as gravity and acceleration. In QFT, time is treated as a fixed parameter, and the creation or annihilation process is described as happening in an instant. Therefore, the two concepts do not have a direct relationship, but they both play important roles in understanding the behavior of particles in the universe.

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