Practical quantum computing requires a scalable hardware platform that allows for the implementation and high-fidelity manipulation (initialization, operation, and readout) of many qubits.

Spin qubits in silicon and germanium quantum dots are leading candidates for large-scale quantum computers. Their strong spin-orbit interaction enables ultrafast all-electric operations, however, their control via microwave pulses introduce critical scaling challenges such as cross-talk and heating.

Exchange-only spin-orbit (XOSO) qubits circumvent these issues by encoding one qubit into three spins in three quantum dots.

This MSc project tackles the question of optimal quantum control of the XOSO qubit and the interaction between multiple XOSO qubits for scalable quantum architectures using novel optimal control approaches. Potential project avenues are:

• Analysis of optimal initialization and single qubit gates
• Investigate the two-qubit interaction and how quantum optimal control can lead to improved fidelity and minimal leakage
• Learn about and compare different optimal control strategies (quantum geometry, Lie algebra, machine learning)
• Study decoherence effects on the XOSO qubit

Figure 1: XOSO qubit planar and linear architectures and their associated energies

Depending on the student’s preferences, this project can be more focused on analytical and/or numerical methods.

For more information about this thesis proposal, you can contact Chris Ventura Meinersen (c.venturameinersen@tudelft.nl)