Sachdev-Ye-Kitaev model on a noisy quantum computer

We study the Sachdev-Ye-Kitaev (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 O (N^5J^2t^2/) where J is the dimensionful coupling parameter, t is the evolution time, and is the desired precision. With this improved resource requirement, we perform the time evolution for N=6, 8 with maximum two-qubit circuit depth and gate count 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 vacuum return probability after time t and out-of-time order correlators which is a standard observable of quantifying the chaotic nature of quantum systems.