Short two-qubit pulse sequences for exchange-only spin qubits in two-dimensional layouts
Jason D. Chadwick, Gian Giacomo Guerreschi, Florian Luthi, Mateusz Tomasz Mądzik, Fahd A. Mohiyaddin, Prithviraj Prabhu, Albert T. Schmitz, Andrew Litteken, Shavindra Premaratne, Nathaniel C. Bishop, A. Y. Matsuura, James S. Clarke · Physical Review A · 2025
Exchange-only (EO) spin qubits in quantum dots offer an expansive design landscape for engineering scalable device layouts. The study of two-EO-qubit operations, which involve six electrons in six quantum dots, has so far been limited to a small number of possible configurations, and previous works lack analyses of design considerations and implications for quantum error correction. Using a simple and fast optimization method, we generate complete pulse sequences for , , i , leakage-controlled , and leakage-controlled two-qubit gates on 450 unique planar six-dot topologies and analyze differences in sequence length (up to 43% reduction) across topology classes. In addition, we show that relaxing constraints on postoperation spin locations can yield further reductions in sequence length; conversely, constraining these locations in a particular way generates a operation with minimal additional cost over a standard . We integrate this pulse library into the Intel quantum stack and experimentally verify pulse sequences on a Tunnel Falls chip for different operations in a linear-connectivity device to confirm that they work as expected. Finally, we explore architectural implications of these results for quantum error correction. Our work guides hardware and software design choices for future implementations of scalable quantum-dot architectures.