Green Alaina M, Elben A, Alderete C Huerta, Joshi Lata Kh, Nguyen Nhung H, Zache Torsten V, Zhu Yingyue, Sundar Bhuvanesh, Linke Norbert M
Joint Quantum Institute and Department of Physics, University of Maryland, College Park, Maryland 20742, USA.
Institute for Quantum Information and Matter and Walter Burke Institute for Theoretical Physics, California Institute of Technology, Pasadena, California 91125, USA.
Phys Rev Lett. 2022 Apr 8;128(14):140601. doi: 10.1103/PhysRevLett.128.140601.
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.
