Gühne, Otfried

Date: Monday, March 14, 2016
Time: 17:00
Place: University of Geneva, external pageGAP UNIGE Seminar roomcall_made  
Host: Nicolas Brunner

Multiparticle entanglement in quantum hyper graph states

Otfried Gühne
University of Siegen, Germany

Hypergraph states form a family of multiparticle quantum states that generalizes the well-known concept of Greenberger-Horne-Zeilinger states, cluster states, and more broadly graph states. Mathematically, these states can conveniently be described by a hyper graph that indicates a possible generation procedure of these states; alternatively, they can also be phrased in terms of a non-local stabilizer formalism.

In this talk I will explore the entanglement properties and nonclassical features of hypergraph states. First, I identify the equivalence classes under local unitary transformations for up to four qubits, as well as important classes of five- and six-qubit states, and determine various entanglement properties of these classes.  Then, I demonstrate that the correlations in hypergraph states can be used to derive various types of nonlocality proofs, including Hardy-type arguments, Bell inequalities for genuine multiparticle nonlocality, and an exponentially increasing violation of local realism. These results suggest that certain classes of hypergraph states are novel resources for quantum metrology and measurement-based quantum computation.