Not necessarily. Ironically, nuclear explosion physics doesn’t use anything from quantum mechanics, nor from relativity. Intellectually, Germans were well-positioned to complete the project; thankfully, they didn’t have the necessary financial and engineering support.

Care to elaborate on that? Sounds rather surprising. In wikipedia on nuclear fission "quantum" is used 3 times: https://en.wikipedia.org/wiki/Nuclear_fission - but I suspect that all of the nuclear physics is based on quantum mechanics isn't it?

I think atemerev's point is that you can find out enough to build a bomb without knowing either relativity or quantum. Yes, E=mc^2 is why the energy is released, but all you need to know is how much energy is released when an atom splits. Yes, quantum mechanics may explain the neutron absorption cross section, but you don't need to know that. You just need to be able to measure the cross section.

Yes, it probably wasn't terribly helpful either that the rejection of Jewish physicists, many of whom helped get the American bomb project off the ground, and rejection of physicists studying "Jewish Physics" left them with probably too few qualified physicists to move a bomb project along as rapidly as the Americans did, even if they had the budget for a project of that size (they didn't), and were willing to spend it early enough (no indication of that). Considering also that they would have had to move rather faster than the Americans, since they didn't finish before the defeat of Germany. Fortunately for the world, there are plenty of reasons why is was essentially impossible for them.

[edited to remove mis-information ] apologies!

Think Un-German, as an English word.