Analysing Multiparticle Quantum States

Abstract

The analysis of multiparticle quantum states is a central problem in quantum information processing. This task poses several challenges for experimenters and theoreticians. We give an overview over current problems and possible solutions concerning systematic errors of quantum devices, the reconstruction of quantum states, and the analysis of correlations and complexity in multiparticle density matrices.

A Variational Principle for Ground Spaces

“…For example, PpU p2q q is not norm closed for three qubits [50]. For a many-body system, the discontinuity of the inference map D pkq Ñ C A is equivalent [56,59,50] to that of a correlation quantity [4,7,61,6,48,44,30] closely related to the "irreducible correlation" first introduced in [38]. For k " 1, the quantity is the mutual information or multi-information, which is continuous and which measures the total correlation [28].…”