We demonstrate a new technique that adapts single-qubit randomized benchmarking to two-qubit M{\o}lmer-S{\o}rensen gates. We use the controllable gate phase to generate Cliffords that act on a two-state subspace, enabling benchmarking of two-qubit gates without single-qubit operations. In addition to quantifying the gate infidelity, the protocol provides valuable information about the type of error by distinguishing between those that conserve the two-state subspace and those that result in leakage out of it. We demonstrate the protocol for calibrating and validating all-electronic maximally entangling gates in a trapped-ion quantum computer, achieving a two-qubit gate error of 2.6(2)×10−4.
@article{arxiv.2510.09508,
title = {Subspace Leakage Error Randomized Benchmarking of M{\o}lmer-S{\o}rensen Gates},
author = {R. T. Sutherland and A. C. Hughes and J. P. Marceaux and H. M. Knaack and C. M. Löschnauer and R. Srinivas},
journal= {arXiv preprint arXiv:2510.09508},
year = {2025}
}