Even if many interesting similarities between the classical and the quantum mechanical framework have been worked out, e.g. in the subject of deformation quantization, in general, there are some ...
Why do things like protons and neutrons have specific values. Also speed of light is a speed in which even if you go towards it, the speed does not vary. But why does light have to travel at speed?
Basically, the book is Brian Cox's Why Does $E=mc^2$?: (And Why Should We Care?). I just finished Chapter 5, where we derived the spacetime momentum vector (energy-momentum four vector, as he ...