Qubit State

A superposition of qubits can be represented as all vectors generated by formal tensor products:

$$({\alpha }_0|0⟩+{\beta }_0|1⟩)\otimes ({\alpha }_1|0⟩+{\beta }_1|1⟩)\otimes \cdots$$

It is considered separable if it could be written in the form above. The general form is:

$$|\Psi ⟩=\sum _{J\in {\mathbb{B}}^n}{\alpha }_J|J⟩$$

where $J$ is a vector of bits, and ${\alpha }_J\in \mathbb{C}$

It is impossible for states to be cloned or forgotten, since all operations have to be reversable.