A physical qubit, for example, an electron with energy level (ground state and excited state) represents a simple quantum system. I was curious whether a physical system is a basis for mathematically representing qubit in 2D space?
Why not a qubit state be in 3D Hilbert space? Is there a mathematical formulation for this even though an equivalent quantum system doesn't exist?
Note: I don't have a formal background in physics or mathematics, this question came to mind when I started reading about quantum computation.