QUROPE Quantum Information Processing and Communication in Europe

Absolutely maximally entangled (AME) states are those multipartite quantum states that carry absolute maximum entanglement in all possible bipartitions. AME states are known to play a relevant role in multipartite teleportation, in quantum secret sharing, and they provide the basis novel tensor networks related to holography.

We show that trace distance measure of coherence is a strong monotone for all qubit and, so called, X states.

The superposition principle is one of the landmarks of quantum mechanics. The importance of quantum superpositions provokes questions about the limitations that quantum mechanics itself imposes on the possibility of their generation. In this work, we systematically study the problem of the creation of superpositions of unknown quantum states.

Let denote the orbit of a complex or real matrix under a certain equivalence relation such as unitary similarity, unitary equivalence, unitary congruences etc.