Holographic study of entanglement and complexity for mixed states

An Entanglement Study of Superposition of Qutrit Spin-Coherent States

Considering generalized concurrence as the criterion of entanglement, we study entanglement properties of superposition of two qutrit coherent states, as a function of their amplitudes. These states may attain maximum entanglement or no entanglement at all, depending on the choice of the parameters involved. The states revealing maximum entanglement also display the maximum violations of the Be...

Catalysis of entanglement manipulation for mixed states

We consider entanglement-assisted remote quantum state manipulation of bipartite mixed states. Several aspects are addressed: we present a class of mixed states of rank two that can be transformed into another class of mixed states under entanglement-assisted local operations with classical communication, but for which such a transformation is impossible without assistance. Furthermore, we demo...

Optimal entanglement criterion for mixed quantum states.

We develop a strong and computationally simple entanglement criterion. The criterion is based on an elementary positive map Phi which operates on state spaces with even dimension N > or = 4. It is shown that Phi detects many entangled states with a positive partial transposition (PPT) and that it leads to a class of optimal entanglement witnesses. This implies that there are no other witnesses ...

Bounding Polynomial Entanglement Measures for Mixed States

Optimal Entanglement Enhancement for Mixed States

We consider the actions of protocols involving local quantum operations and classical communication (LQCC) on a single system consisting of two separated qubits. We give a complete description of the orbits of the space of states under LQCC and characterise the representatives with maximal entanglement of formation. We thus obtain a LQCC entanglement concentration protocol for a single given st...