Within less than a decade, we went from demonstrating fission to using nukes in a war. In the decades since, has any leap of a similar nature beyond nukes been theorized; something like a step beyond the step from fission atom bombs to fission/fusion hydrogen bombs? I'm not sure why we'd ever need it, but it seems that given the time, maybe we would have at least pondered how to do it. Askscience didn't have any input, and suggested I post this question here.
This is a chemistry/physics question. For any mass, the energy contained is equal to the mass multiplied by the square of the speed of light (the famed e=mc2 equation). This defines the physical limit of how much energy can be harvested from a given mass (of any substance). The characteristics of the substance in question and the methodology of the energy extraction contribute to the efficiency of energy extraction. At this point in time, I don't believe that there is a more efficient method of energy extraction than fusion. In order for explosions to become magnitudes more powerful than what's already been created, there either must be an increase in the efficiency of creating fusion or a discovery of another method of harvesting energy from a mass.
I opted to respond to you in your previous /r/AskScience post, and it seems to have been recently deleted. Let me know if for some reason replies to deleted threads don't reach you.