Surface-electrode ion trap design for near-field microwave quantum gates

• Published in: Applied physics. B, Lasers and optics Lasers and optics, 2023-06, Vol.129 (6), Article 89
• Main Authors: Tarlton, James E., Thompson, Richard C., Lucas, David M.
• Format: Article
• Language: English
• Subjects: Applied physics; Boundary conditions; Calcium isotopes; Design optimization; Electrodes; Engineering; Ground plane; Lasers; Microwave frequencies; Near fields; Optical Devices; Optics; Photonics; Physical Chemistry; Physics; Physics and Astronomy; Quantum Optics; Qubits (quantum computing)
• ISSN: 0946-2171; 1432-0649
• DOI: 10.1007/s00340-023-08030-x

We present a design study into an ion trap electrode geometry for applying near-field microwave two-qubit gates. This design features an ‘S’-shaped meander electrode to passively null the microwave field. It has ground planes separating the meander electrode from all of the DC and single-qubit microwave electrodes, which should reduce the sensitivity of the microwave field distribution to the boundary conditions of these electrodes. We show that it is possible to design a single-layer trap with this geometry such that the simulated microwave field null overlaps with the RF field null, and that the positions of these nulls can be simulated to a precision of 100 nm with moderate computing resources. We also show that such a trap can be designed such that ion chains can be trapped, transported and split with feasible DC and RF voltages. While this particular design is optimized for 43 Ca + ions, our approach could be applied to other ions by changing the microwave frequency to match the corresponding qubit transition frequency.