Berlin 2024 – scientific programme

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QI: Fachverband Quanteninformation

QI 2: Semiconductor Qubits (joint session QI/HL)

QI 2.10: Talk

Monday, March 18, 2024, 12:30–12:45, HFT-FT 131

Gate operations on Exchange-Only spin qubits with oscillating drive — •Tobias Heinz, Stephen R. McMillan, and Guido Burkard — Department of Physics, University of Konstanz, D-78457 Konstanz, Germany

A major obstacle on the path towards large-scale quantum computing lies in achieving high fidelities for gate operations. Spin qubits using exchange interaction alone have emerged as promising candidates [1] due to their resistance to certain types of decoherence [2]. Motivated by the proposed gate of Doherty and Wardrop [3], this work focuses on the application of an oscillating drive field to facilitate an entangling two qubit operation between two local Resonant-Exchange qubits. By driving the exchange interaction belonging to one qubit, we propose a CNOT gate for universal quantum computing, with gate times in the range of a hundred nanoseconds. We analyze the impact of the drive amplitude on gate fidelity and gate time, providing insights into the optimal parameter regimes. Through numerical simulations, we determine the impacts of leakage and off-resonant processes on the fidelity. For context, we compare our results to a static gate obtained through a dc pulse of the interqubit exchange coupling. Our proposal contributes to the understanding of the implementation of spin qubits and paves the way for the development of robust and scalable quantum computers. [1] G. Burkard et al. Rev. Mod. Phys. 95, 025003 (2023). [2] J. M. Taylor et al. Phys. Rev. Lett. 111, 050502 (2013). [3] A. C. Doherty et al. Phys. Rev. Lett. 111, 050503 (2013).

Keywords: Exchange-Only qubits; Resonant-Exchange qubits; Gate fidelity; Leakage and off-resonant processes