Why does a single qubit need to be a unit vector on the bloc sphere? Why can't it be a unit vector on a circle?
If we had the quantum bits with only 2 degrees of freedom (no imaginary part) could we still perform all possible quantum calculations with them, maybe just using more bits than the equivalent system with full qubits?
Intuitively i feel like entanglement and collapse and everything should all work.
Is it just because these 2d qubits don't exist anywhere in nature?