None. Einstein was a theoretician.

gramsci is called theoretician of super structure because he criticised the theory of marx who emphasised upon the importance of sub structure. in opposition to this gramsci said that super structure plays an inpependant role in determining the society.here super strucyure refer to the "ideas"...

Nothing. He was an engineer and marketeer that designed and sold computers. He was neither a scientific experimentalist nor theoretician.

They are used to model various situations where it is believed that some infinite "branching" effect best describes the geometry. For examples of how I have employed fractals as a theoretician, check out the "related links" included with this answer. I hope you like what you see.

The question is probably intended to cue the answer "Niels Bohr", but it could apply to almost any subsequent theoretician of atomic structure.