Frequency-robust Mølmer–Sørensen Gates via Motional Mode Balancing

Trapped ions are one of the most promising platforms for quantum computing with high-fidelity entangling gates having been demonstrated on many systems. However, maintaining high fidelity as the length of the ion chain grows remains a challenge due to an increased density of motional modes, intensifying the need to stabilize their frequencies. A variety of techniques have been developed to provide frequency robustness of a few kHz to gate performance, but they typically require optimizing a large set of pulse-shape parameters. In this talk, we introduce a technique that extends this range of robustness by an order of magnitude without requiring a many-parameter optimization process. Our technique employs a Mølmer–Sørensen gate with Gaussian amplitude modulation and a specific choice of detuning that balances the contributions from all motional modes to provide optimal frequency robustness. We experimentally demonstrate our gate on a three-ion chain and analyze the scalability of our gate through numerical simulations on chains up to 33 ions.



This material was funded by the U.S. DOE, Office of Science, ASCR Quantum Testbed Program. SNL is managed and operated by NTESS LLC, a subsidiary of Honeywell International, Inc., for the U.S. DOE's NNSA under contract DE-NA0003525. The views expressed here do not necessarily represent the views of the DOE or the U.S. Government.