2026-06-08T12:24:57Zhttps://docta.ucm.es/rest/oai/request

oai:docta.ucm.es:20.500.14352/120402024-08-27T16:54:20Zcom_20.500.14352_14col_20.500.14352_15

00925njm 22002777a 4500 dc Viyuela, O. author Rivas, A. author Gasparinetti, S. author Wallraff, A. author Filipp, S. author Martín-Delgado Alcántara, Miguel Ángel author 2018-02-12 Topological insulators and superconductors at finite temperature can be characterized by the topological Uhlmann phase. However, a direct experimental measurement of this invariant has remained elusive in condensed matter systems. Here, we report a measurement of the topological Uhlmann phase for a topological insulator simulated by a system of entangled qubits in the IBM Quantum Experience platform. By making use of ancilla states, otherwise unobservable phases carrying topological information about the system become accessible, enabling the experimental determination of a complete phase diagram including environmental effects. We employ a state-independent measurement protocol which does not involve prior knowledge of the system state. The proposed measurement scheme is extensible to interacting particles and topological models with a large number of bands. 2056-6387 10.1038/s41534-017-0056-9 https://hdl.handle.net/20.500.14352/12040 http://dx.doi.org/10.1038/s41534-017-0056-9 https://www.nature.com Observation of topological Uhlmann phases with superconducting qubits