Sachdev-Ye-Kitaev model on a noisy quantum computer

TL;DR

This paper implements the Sachdev-Ye-Kitaev (SYK) model on IBM quantum computers, optimizing gate complexity and applying error mitigation to study quantum chaos indicators like OTOCs.

Contribution

It introduces a graph-coloring algorithm to reduce gate complexity for simulating the SYK model on noisy quantum hardware.

Findings

Gate complexity scales as O(N^5 J^2 t^2 / ε) for the SYK model.

Successfully performed time evolution for N=6, 8 with shallow circuits.

Achieved good agreement with classical results after error mitigation.

Abstract

We study the SYK model -- an important toy model for quantum gravity on IBM's superconducting qubit quantum computers. By using a graph-coloring algorithm to minimize the number of commuting clusters of terms in the qubitized Hamiltonian, we find the gate complexity of the time evolution using the first-order product formula for $N$ Majorana fermions is $\mathcal{O}(N^5 J^{2}t^2/\epsilon)$ where $J$ is the dimensionful coupling parameter, $t$ is the evolution time, and $\epsilon$ is the desired precision. With this improved resource requirement, we perform the time evolution for $N=6, 8$ with maximum two-qubit circuit depth of 343. We perform different error mitigation schemes on the noisy hardware results and find good agreement with the exact diagonalization results on classical computers and noiseless simulators. In particular, we compute return probability after time $t$ and out-of-time order correlators (OTOC) which is a standard observable of quantifying the chaotic nature of quantum systems.