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masteralien

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- TL;DR Summary
- Is it possible to use the Wigner Weisskopf method for transitions from a discrete state to a continuum in the case of a time varying perturbation.

In Time Dependent Perturbation Theory for coupling of a discrete state to a continuum you use the Wigner Weisskopf method to describe how the initial state gets depopulated and final states populated and the line shape for the case of a constant step potential perturbation. However many cases of coupling to a continuum like photoionization aren’t described by a constant perturbation rather a harmonic one. Can this method be extended to a time varying perturbation for example harmonic or exponential. If so are there any sources books, lecture notes, and papers which discuss Wigner Weisskopf method for time varying perturbations for example the line width and wavefunction evolution for a continuum transition in the case of a time varying perturbation say a sinusoidal one for photoionization. Presumably you would just insert into the integral when applying the Wigner Weisskopf approximation the temporal part of the Hamiltonian the same way you do for a constant perturbation, if so are there any sources which discuss this to make sure this is the correct approach. Also does this method even work for time varying Perturbations.