Under very specific circumstances: >The radiative properties of an atom in a cavity differ fundamentally from the atom's radiative properties in free space. Sp

Under very specific circumstances: >The radiative properties of an atom in a cavity differ fundamentally from the atom's radiative properties in free space. Spontaneous emission is inhibited if the cavity has characteristic dimensions which are small compared to the radiation wavelength, and enhanced if the cavity is resonant. The cavity causes slight shifts in the energies of the atom, analogous to radiative shifts. [0] I wouldn't classify it under radioactive decay as in "nuclear change" (here: Potassium-40 as beta minus decay and EC, respectively) as it is a well understood photon-matter-interaction phenomenona (cQED) in e.g. manipulating single photons (single atoms in cavity) deterministically [1] which can be used in turn - coincidentally - in generating true random numbers ... [2] [0]https://ui.adsabs.harvard.edu/abs/1981PhRvL..47..233K/abstract https://ui.adsabs.harvard.edu/abs/1981PhRvL..47..233K/abstra... [1]https://www.nature.com/articles/nphys569 https://www.nature.com/articles/nphys569 [2]https://aip.scitation.org/doi/10.1063/1.3610677 https://aip.scitation.org/doi/10.1063/1.3610677