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Observation of topological Uhlmann phases with superconducting qubits

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Viyuela, O. and Rivas, A. and Gasparinetti, S. and Wallraff, A. and Filipp, S. and Martin-Delgado Alcántara, Miguel Ángel (2018) Observation of topological Uhlmann phases with superconducting qubits. NPJ quantum information, 4 . ISSN 2056-6387

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Official URL: http://dx.doi.org/10.1038/s41534-017-0056-9




Abstract

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.


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© All authors. M.A.M.D., A.R. and O.V. thank the Spanish MINECO grant FIS2012-33152, a “Juan de la Cierva-Incorporación” reseach contract, the CAM research consortium QUITEMAD+ S2013/ICE-2801, the U.S. Army Research Office through grant W911NF-14-1-0103, Fundación Rafael del Pino, Fundación Ramón Areces, and RCC Harvard. S.G., A.W. and S.F. acknowledge support by the Swiss National Science Foundation (SNF, Project 150046).

Uncontrolled Keywords:HGTE quantum-wells; Berrys phase; State; Insulators; Systems; Bands
Subjects:Sciences > Physics > Physics-Mathematical models
ID Code:47210
Deposited On:24 Apr 2018 15:22
Last Modified:25 Apr 2018 07:42

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