What if one were to create a laws of physics emulator, and then inside of it, assemble a brain from atoms/particles/etc ? Or would it suffice to create a neuro

What if one were to create a laws of physics emulator, and then inside of it, assemble a brain from atoms/particles/etc ? Or would it suffice to create a neuron emulator, and build a brain inside of it? Could you train an AI on brain scans pulled from people thinking about various topics, and then have the AI direct the neuron emulator. I'm just spitballing ideas with very little knowledge of how brains actually work.