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Published April 8, 2022 | Published + Submitted + Supplemental Material
Journal Article Open

Experimental Measurement of Out-of-Time-Ordered Correlators at Finite Temperature

Abstract

Out-of-time-ordered correlators (OTOCs) are a key observable in a wide range of interconnected fields including many-body physics, quantum information science, and quantum gravity. Measuring OTOCs using near-term quantum simulators will extend our ability to explore fundamental aspects of these fields and the subtle connections between them. Here, we demonstrate an experimental method to measure OTOCs at finite temperatures and use the method to study their temperature dependence. These measurements are performed on a digital quantum computer running a simulation of the transverse field Ising model. Our flexible method, based on the creation of a thermofield double state, can be extended to other models and enables us to probe the OTOC's temperature-dependent decay rate. Measuring this decay rate opens up the possibility of testing the fundamental temperature-dependent bounds on quantum information scrambling.

Additional Information

© 2022 American Physical Society. (Received 3 December 2021; revised 3 February 2022; accepted 9 March 2022; published 6 April 2022) A. E. acknowledges funding by the German National Academy of Sciences Leopoldina under the Grant No. LPDS 2021-02 and by the Walter Burke Institute for Theoretical Physics, Caltech. L. K. J. acknowledges the European Union's Horizon 2020 research and innovation programme under Grant Agreement No. 731473 (QuantERA via QT-FLAG) and the Austrian Science Foundation (FWF, P 32597 N). T. V. Z.'s work is supported by the Simons Collaboration on Ultra-Quantum Matter, which is a grant from the Simons Foundation (651440, P. Z.). This work received support from the National Science Foundation through the Quantum Leap Challenge Institute for Robust Quantum Simulation (OMA-2120757) and the Physics Frontier Center (PHY-1430094) at the Joint Quantum Institute (JQI). A. M. G. is supported by a JQI Postdoctoral Fellowship. N. M. L. acknowledges funding by the Maryland-Army-Research-Lab Quantum Partnership (W911NF1920181), the Department of Energy, Office of Science, Office of Nuclear Physics (DE-SC0021143), and the Office of Naval Research (N00014-20-1-2695). We thank Ana Maria Rey and Murray Holland for a careful reading of the manuscript.

Attached Files

Published - PhysRevLett.128.140601.pdf

Submitted - 2112.02068.pdf

Supplemental Material - GreenOTOCSupp.pdf

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Additional details

Created:
August 22, 2023
Modified:
October 23, 2023