Simulating Floquet scrambling circuits on trapped-ion quantum computers

TL;DR

This paper demonstrates the simulation of quantum information scrambling using Floquet circuits on 20-qubit trapped-ion quantum computers, confirming theoretical predictions and benchmarking current quantum hardware capabilities.

Contribution

It introduces experimental implementation of Floquet scrambling circuits on trapped-ion processors, validating theoretical protocols and showcasing the hardware's performance.

Findings

Confirmed growth of signals in Hayden-Preskill protocol

Observed decay of out-of-time-ordered correlators

Demonstrated calculation of local operator expectation values

Abstract

Complex quantum many-body dynamics spread initially localized quantum information across the entire system. Information scrambling refers to such a process, whose simulation is one of the promising applications of quantum computing. We demonstrate the Hayden-Preskill recovery protocol and the interferometric protocol for calculating out-of-time-ordered correlators to study the scrambling property of a one-dimensional kicked-Ising model on 20-qubit trapped-ion quantum processors. The simulated quantum circuits have a geometrically local structure that exhibits the ballistic growth of entanglement, resulting in the circuit depth being linear in the number of qubits for the entire state to be scrambled. We experimentally confirm the growth of signals in the Hayden-Preskill recovery protocol and the decay of out-of-time-ordered correlators at late times. As an application of the created scrambling circuits, we also experimentally demonstrate the calculation of the microcanonical expectation values of local operators adopting the idea of thermal pure quantum states. Our experiments are made possible by extensively utilizing one of the highest-fidelity quantum processors currently available and, thus, should be considered as a benchmark for the current status of the most advanced quantum computers.