QFT and Electrons: Is Instantaneous Orbital Change Possible?

In summary, the time for an electron to move to a higher orbital is not instantaneous. There is a finite time it takes to move from one orbital to the next.
  • #1
maverick_starstrider
1,119
6
My mathematical knowledge of QFT is nonexistant (I'm only just starting grad school) so I was wondering if anyone could clear up a questions I have:

1) Can the time it takes for an electron (which has just absorbed a photon of the correct frequency) to move to a higher orbital be said to be instantaneous?

Naively one would expect so since the wavefunction of the two orbitals are quantized and thus one would think that there is no 'intermediate' quantum state through which it can time-evolve through. However, if it is instantaneous would that not potentially lead to a relativistic violation?
 
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  • #2
I am aware that the presence of matter slows down light's effective speed due to the time spent during refraction.
I don't know if the electron state change itself is instantaneous, but I know the photon absorption and re-emission is not.
 
  • #3
Is this necessarily true (I don't know) or is it rather that light re-emitted experiences a phase shift?
 
  • #4
It is very true. The value of c is the speed of light in a vacuum. The effective speed a light beam takes to travel through matter is slower because of the cumulative time spent refracting off atoms. For example, it takes tens of thousands of years for photons generated inside the Sun's core to complete their random walk and escape because they interact so frequently with the dense plasma.
 
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  • #5
That's a rather simplistic model of why the speed of light is less in a medium. I believe there's a sticky about that. I'm considering a single absorption event.
 
  • #6
Sorry. I tried.
 
  • #7
maverick_starstrider said:
1) Can the time it takes for an electron (which has just absorbed a photon of the correct frequency) to move to a higher orbital be said to be instantaneous?

No, not quite. Remember that the only thing we can calculate is the probability to find the electron in the higher orbital as a function of time. That probability varies between 0 and 1 at the Rabi frequency, which in turn depends on the dipole moment for the transition and the amplitude of the drive field.
Note that this is true even if you consider a single atom and a single photon, the best example of this can be found in cavity-QED experiments where the Rabi frequency is simply twice the coupling strength/h between the cavity and the atom.
 

1. What is QFT and how does it relate to electrons?

QFT stands for Quantum Field Theory, which is a theoretical framework used to describe the behavior of particles at the quantum level. Electrons are fundamental particles that are described by QFT, and their interactions with other particles can be explained using this theory.

2. Can electrons change orbitals instantaneously?

According to classical physics, electrons can only change orbitals by jumping from one energy level to another. However, in the quantum world, there is a probability of an electron being found in a certain orbital at any given time. So, while it is not instantaneous, electron orbitals can change rapidly due to their wave-like nature.

3. Is there any evidence of instantaneous orbital change in electrons?

Currently, there is no direct evidence of instantaneous orbital change in electrons. However, experiments have shown that electrons can transition between orbitals in a very short amount of time, leading to the speculation that instantaneous orbital change may be possible in certain conditions.

4. What are the implications of instantaneous orbital change in QFT?

If instantaneous orbital change is possible, it would challenge our current understanding of quantum mechanics and could potentially lead to new discoveries and applications. It could also have implications for technologies that rely on precise control of electronic transitions, such as transistors in electronic devices.

5. How does QFT explain the behavior of electrons in atoms?

QFT describes electrons as quantum fields, meaning they exist in a state of superposition and can exhibit wave-like behavior. This allows for a better understanding of how electrons move and interact within an atom, including their orbital changes and energy levels.

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