The structure of superqubit states

Superqubits provide a supersymmetric generalisation of the conventional qubit in quantum information theory. After a review of their current status, we address the problem of generating entangled states. We introduce the global unitary supergroup UOSp((3ⁿ+1)/2/(3ⁿ?1)/2) for an n-superqubit system, which contains as a subgroup the local unitary supergroup [UOSp(2/1)]ⁿ. While for 4 > n > 1 the bosonic subgroup in UOSp((3ⁿ + 1)/2/(3ⁿ ? 1)/2) does not contain the standard global unitary group SU(2ⁿ), it does have an USp(2ⁿ) ⊂ SU(2ⁿ) subgroup which acts transitively on the n-qubit subspace, as required for consistency with the conventional multi-qubit framework. For two superqubits the UOSp(5/4) action is used to generate entangled states from the "bosonic" separable state /00}.