3 research outputs found
Macroscopic Observables Detecting Genuine Multipartite Entanglement and Partial Inseparability in Many-Body Systems
We show a general approach for detecting genuine multipartite entanglement
(GME) and partial inseparability in many-body-systems by means of macroscopic
observables (such as the energy) only. We show that the obtained criteria, the
"GME gap" and "the k-entanglement gap", detect large areas of genuine
multipartite entanglement and partial entanglement in typical many body states,
which are not detected by other criteria. As genuine multipartite entanglement
is a necessary property for several quantum information theoretic applications
such as e.g. secret sharing or certain kinds of quantum computation, our
methods can be used to select or design appropriate condensed matter systems.Comment: 4 pages, 3 figures, published version, title extende
Magnetic Susceptibility as a Macrosopic Entaglement Witness
We show that magnetic susceptibility can reveal spin entanglement between
individual constituents of a solid, while magnetisation describes their local
properties. We then show that these two thermodynamical quantities satisfy
complementary relation in the quantum-mechanical sense. It describes sharing of
(quantum) information in the solid between spin entanglement and local
properties of its individual constituents. Magnetic susceptibility is shown to
be a macroscopic spin entanglement witness that can be applied without complete
knowledge of the specific model (Hamiltonian) of the solid.Comment: 6 Pages, 2 figures, revtex