Variability and Fidelity Limits of Silicon Quantum Gates Due to Random Interface Charge Traps

TL;DR

This paper models how random interface charge traps affect the fidelity of silicon quantum gates, showing that high-fidelity operation is achievable with current interface quality and composite pulses, despite device variability.

Contribution

Develops a microscopic stochastic simulation method to analyze the impact of random charge traps on silicon quantum gate fidelity, highlighting variability effects and potential improvements.

Findings

Two-qubit gates achieve >98% fidelity with 75% probability

Fidelity can be improved to >99.5% using composite pulses

Device variability is mainly due to small number of traps per device

Abstract

Silicon offers an attractive material platform for hardware realization of quantum computing. In this study, a microscopic stochastic simulation method is developed to model the effect of random interface charge traps in silicon metal-oxide-semiconductor (MOS) quantum gates. The statistical results show that by using a fast two-qubit gate in isotopically purified silicon, the two-qubit silicon-based quantum gates have the fidelity >98% with a probability of 75% for the state-of-the-art MOS interface quality. By using a composite gate pulse, the fidelity can be further improved to >99.5% with the 75% probability. The variations between the quantum gate devices, however, are largely due to the small number of traps per device. The results highlight the importance of variability consideration due to random charge traps and potential to improve fidelity in silicon-based quantum computing.