Noise-Aware Circuit Compilations for a Continuously Parameterized Two-Qubit Gateset*

Sandia National Laboratories is home to the Quantum Scientific Computing Open User Testbed (QSCOUT), a low-level quantum computing testbed based on a linear chain of trapped ¹⁷¹Yb+ ions. As part of the DOE ASCR Quantum Testbed Program, QSCOUT aims to offer transparency and versatility in exploring quantum algorithms on a noisy-intermediate-scale quantum (NISQ) system and is bolstered by access at a variety of levels within the software stack as deep as pulse-level control. Our all-to-all connected qubit register is hosted by a microfabricated surface-electrode trap, and gates are realized via individually addressed optical Raman transitions. QSCOUT offers continuous parameterization of the two-qubit Mølmer-Sørensen (MS) gate, which has been crucial to a number of recent user collaborations. Here, I will discuss the empirical realization, error sources, and the frequency robustness of our continuously parameterized MS gate, as well as a recent effort to mitigate crosstalk from individual addressing beams. Combining these efforts, we then use Superstaq to develop and study noise-aware compilations focused on the continuously parameterized MS gates. These include swap mirroring to reduce total entangling angle contained in the circuit as well as focusing the heaviest MS angle participation on the best performing gate pairs and/or qubits. From these efforts, we realize distinct improvements in system performance. To conclude, I will present a roadmap of future planned developments to broaden QSCOUT’s offerings, including mid-circuit measurements and multi-qubit entangling gates.