CRM: Centro De Giorgi
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Quantum Information and Many-Body Quantum Systems

seminar: Energy, Entanglement, and Information Transfer in Many-Body Systems

speaker: Fabrizio Illuminati (Dipartimento di Fisica "E. R. Caianiello", Università degli Studi di Salerno)

abstract: We report on recent progress in the understanding and use of ground state entanglement in interacting quantum systems. We first discuss necessary and sufficient conditions for the separability of the ground state that hold in general for translationally-invariant systems. The necessary and sufficient criterion is provided by the vanishing of the excitation energy associated to suitable unitary operations performed on a single subsystem. We then show that such excitation energy not only qualifies, but as well determines quantitatively the amount of entanglement present in the ground state and its behavior at the approach of a quantum critical point. We thus provide: 1) a general criterion for the classicality of quantum ground states; 2) a first explicit and direct connection between two universal physical resources, energy and entanglement, in quantum many-body systems; 3) an independent characterization of entanglement by macroscopic observables amenable to direct experimental determination. We then move on to consider generic criteria and feasible schemes for long-distance entanglement and robust information transfer in interacting spin systems. In particular, we investigate the sensitivity of end-to-end entanglement to different engineerings of coupling constants, the presence of imperfections, the role of temperature, and mappings with models of interacting atoms in optical lattices.


timetable:
Wed 28 Mar, 9:50 - 10:20, Aula Dini
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