Here are some definitions and terms of things: 

- bloch's theorem - an unbound electron moves in a periodic potential  as a free  electron in a vacuum 
- **quantum jump**
	- abrupt transition of an electron, or atom, or molecules from one quantum state to another 
	- supposedly unpredictable, no one can know when the next quantum jump will be 


- **tensor products** 
	- way of calculating amplitudes