Measuring multipartite entanglement through dynamic susceptibilities

By Philipp Hauke, Markus Heyl, Luca Tagliacozzo, Peter Zoller. Nature Physics, 2015

384 citations recorded by the source corpus.

Entanglement is considered an essential resource in quantum technologies, and central to the understanding of quantum many-body physics. Developing protocols to detect and quantify the entanglement of many-particle quantum states is thus a key challenge for present experiments. Here, we show that the quantum Fisher information, a witness for genuinely multipartite entanglement, becomes measurable for thermal ensembles by means of the dynamic susceptibility—that is, with resources readily available in present cold atomic-gas and condensed-matter experiments. This establishes a connection between multipartite entanglement and many-body correlations contained in response functions, with immediate implications close to quantum phase transitions, where the quantum Fisher information becomes universal, allowing us to identify strongly entangled phase transitions with a divergent multipartite entanglement. We illustrate our framework using paradigmatic quantum Ising models, and point out potential signatures in optical-lattice experiments and strongly correlated materials. Entanglement in many-body systems is notoriously hard to quantify, but in certain situations relevant to atomic and condensed-matter experiments an entanglement witness, the quantum Fisher information, becomes measurable by means of the dynamic susceptibility.

Subfields: Atomic and Molecular Physics, and Optics, Condensed Matter Physics

View Paper: https://www.semanticscholar.org/paper/f1512c071d38af49b81793d387160deed6b431cd

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In Atomic and Molecular Physics, and Optics

In Condensed Matter Physics

Citations in the corpus

Macroscopic quantum states: Measures, fragility, and implementations (2017, background): “One example is Hauke et al. (2016), where it is shown that the quantum Fisher information can be obtained by means of the dynamic susceptibility, and can be used to detect entanglement during phase transitions.”
Entanglement certification from theory to experiment (2018, background): “[295] Philipp Hauke, Markus Heyl, Luca Tagliacozzo, and Peter Zoller, “Measuring multipartite entanglement through dynamic susceptibilities,” Nat.”
At the limits of criticality-based quantum metrology: apparent super-Heisenberg scaling revisited (2017, methodology): “The entanglement detection method has recently found a new application in the proposal to extract the Fisher information from a dynamical susceptibility of the thermal input state [27] (see also Ref.”
Quantum Fisher information matrix and multiparameter estimation (2019, background): “This appendix gives the thorough calculation of the relation between QFIM and dynamic susceptibility in reference [109].”
Quantum metrology with nonclassical states of atomic ensembles (2016, background): “The quantum Fisher information has also been related to the dynamical susceptibility (Hauke et al., 2016), while”