I was reading through the section on spontaneous emission in a book by Griffiths. In it he explained that spontaneous emission is really a stimulated emission except the cause of it is the electrons in the ground state that provide the perturbing radiations to initiate an emission. He commented that due to the ground state energy, there still will be some EM radiation even when it is completely dark and at absolute zero temperature.
I do understand that the Electric field will be present since the electron is a charged particle, but how could radiation be present due to the ground state electron? From my understanding, radiation is caused by acceleration of electron. And the electron in an atom maintains its constant movement since its kinetic energy is conserved. Then since the electron will retain constant velocity (I know this may not be in reality but in terms of energy conservation) and does not accelerate, creating no EM radiation. Also if it were radiating, shouldn't the ground state electrons lose energy? After a thought I personally came to a conclusion that when an electron moves down the energy level, it's relative distance to the ground state electron decreases so gains some potential which could compensate for the emitted energy that served as the perturbation. But How would the ground state electron radiate energy if for a minuscule amount in time it's total energy would differ from the quantized amount of ground state energy? Also is the conclusion I've come down to a correct way to view this phenomenon?