We introduce the concept of pairwise tomography networks to characterise quantum properties in many-body systems and demonstrate an efficient protocol to measure them experimentally. Pairwise tomography networks are generators of multiplex networks where each layer represents the graph of a relevant quantifier such as, e.g., concurrence, quantum discord, purity, quantum mutual information, or classical correlations. We propose a measurement scheme to perform two-qubit tomography of all pairs showing exponential improvement in the number of qubits N with respect to previously existing methods. We illustrate the usefulness of our approach by means of several examples revealing its potential impact to quantum computation, communication and simulation. We perform a proof-of-principle experiment demonstrating pairwise tomography networks of W states on IBM Q devices.
@article{arxiv.1909.12814,
title = {Pairwise tomography networks for many-body quantum systems},
author = {Guillermo García-Pérez and Matteo A. C. Rossi and Boris Sokolov and Elsi-Mari Borrelli and Sabrina Maniscalco},
journal= {arXiv preprint arXiv:1909.12814},
year = {2020}
}