If I understand special relativity correctly, when we accelerate an object around earth (or back and forth to another planet), the clock on the projectile will slow down and thus effectively time would be slower and the people on the projectile couldn't get as much done (as they have less time) r...

I did understand the historical reasons for the discovery of antiparticles in this context. But are antiparticles really a 'consequence' of combining special relativity and quantum theory? Why isn't it better to say that the existence of antiparticles are consistent with QM and SR?

If we solve the time independent Schrödinger equation for a particle in a box of length $L$, we get: $$\psi_n\left(x\right)=A\sin\left(\frac{\pi n}{L}x\right)$$ I then see that we normalize $A$ such that: $$A=\sqrt{\frac{2}{L}}$$ so that the sum of the probabilities is $1$. My question is, why i...