Experimental Bayesian calibration of trapped ion entangling operations

TL;DR

This paper presents an efficient Bayesian calibration protocol for trapped ion quantum gates, achieving high precision with minimal experimental cycles and rapid calibration times, applicable to various quantum architectures.

Contribution

The authors develop and experimentally validate a Bayesian calibration method for Molmer-Sorensen gates that reduces calibration time and improves accuracy in trapped ion quantum processors.

Findings

Median gate infidelity of 1.3e-3 achieved

Calibration completed in less than one minute

Requires approximately 1200 experimental cycles

Abstract

The performance of quantum gate operations is experimentally determined by how correct operational parameters can be determined and set, and how stable these parameters can be maintained. In addition, gates acting on different sets of qubits require unique sets of control parameters. Thus, an efficient multi-dimensional parameter estimation procedure is crucial to calibrate even medium sized quantum processors. Here, we develop and characterize an efficient calibration protocol to automatically estimate and adjust experimental parameters of the widely used Molmer-Sorensen entangling gate operation in a trapped ion quantum information processor. The protocol exploits Bayesian parameter estimation methods which includes a stopping criterion based on a desired gate infidelity. We experimentally demonstrate a median gate infidelity of $1.3(1)\cdot10^{-3}$, requiring only $1200\pm500$ experimental cycles, while completing the entire gate calibration procedure in less than one minute. This approach is applicable to other quantum information processor architectures with known or sufficiently characterized theoretical models.