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

TL;DR

This paper presents an experimental method to measure out-of-time-ordered correlators at finite temperatures using a digital quantum computer, enabling exploration of quantum information scrambling and temperature effects.

Contribution

The authors introduce a novel thermofield double state-based technique for measuring OTOCs at finite temperatures on quantum simulators.

Findings

Successfully measured OTOCs at different temperatures.

Demonstrated the temperature dependence of OTOC decay rates.

Method can be extended to other quantum models.

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.