Does it make sense to speak of the probability of finding a system which was once in the ground state in a higher state after a certain time? Since the Hamiltonian depends on time, once you collapse the wavefunction at that time, the energy you get can't be one of the values of the unperturbed system, but rather the allowed values for the Hamiltonian at the moment you collapse the wavefunction.(adsbygoogle = window.adsbygoogle || []).push({});

For example, take beta decay, where the nucleus gets an extra positive charge and an electron flies out. Because this process happens so quick, the state of a orbital electron in the ground state remains there, but that doesn't mean it has that energy, but instead one has to write the ground state of the unperturbed system as a linear combination of the energy eigenstates for a postive ion nucleus?

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# Transition probabilities (basic concepts no math)

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