To realize practical quantum computation, a set of high-fidelity universal quantum gates robust against noise and uncertainty in a qubit system is prerequisite. Constructing control pulses to operate quantum gates which meet this requirement is an important and timely issue. In most robust control methods, noise is assumed to be quasi-static, i.e., is time-independent within the gate operation time but can vary between different gates. But this quasi-static- noise assumption is not always valid. Here we develop a systematic method to find pulses for quantum gate operations robust against stochastic time-varying noise. Our approach, taking into account the noise properties of quantum computing systems, can output single smooth pulses in the presence of multi-sources of noise. Furthermore, our method can be applied to different system models and noise models, and will make essential steps toward constructing high-fidelity and robust quantum gates for fault-tolerant quantum computation (FTQC). As a practical example, we apply our robust control method to construct high-fidelity and robust single-qubit and two-qubit gates for a realistic system of quantum-dot electron spin qubits in silicon.
Chia-Hsien Huang received his Ph.D. in Physics from National Taiwan University in 2017, and his advisor was Professor Hsi-Sheng Goan. His research area is in quantum computation. Currently, he is a postdoctoral fellow of National Taiwan University, and focuses on developing high-fidelity and robust quantum gates for superconducting qubits and semiconductor quantum-dot electron spin qubits.