On the stratifications of 2-qubits X-state space

Abstract

The 7-dimensional family ${\mathfrak{P}}_X$ of so-called mixed X-states of 2-qubits is considered. Two types of stratification of 2-qubits $X-$state space, i.e., partitions of ${\mathfrak{P}}_X$ into orbit types with respect to the adjoint group actions, one of the global unitary group $G_X\subset SU(4)$ and another one under the action of the local unitary group $L{G}_X\subset G_X$, is described. The equations and inequalities in the invariants of the corresponding groups, determining each stratification component, are given.

References in corpus (1)

• Local unitary transformation, long-range quantum entanglement, wave function renormalization, and topological order