Silicon-based spin qubit platform is a promising candidate for the hardware realization of quantum computing. Charge noise, however, plays a critical role in limiting the fidelity and scalability of silicon-based quantum computing technologies. This work presents Green’s transfer function approach to simulate the correlated noise power spectral density (PSD) in silicon spin qubit devices. The simulation approach relates the dynamics of the charge noise source of two-level fluctuators (TLFs) to the correlated noise of spin qubit device characteristics through a transfer function. It allows the noise auto-correlation and cross correlation between any pairs of physical quantities of interest to be systematically computed and analyzed. Because each spin qubit device involves only a small number of TLFs due to its nanoscale device size, the distribution of TLFs impacts the noise correlation significantly. In both a two-qubit quantum gate and a spin qubit array device, the charge noise shows strong cross correlation between neighboring qubits. The simulation results also reveal a phase-flipping feature of the noise cross-PSD between neighboring spin qubits, consistent with a recent experiment.
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Variability and Fidelity Limits of Silicon Quantum Gates Due to Random Interface Charge Traps
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.
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- Award ID(s):
- 2007200
- PAR ID:
- 10294867
- Date Published:
- Journal Name:
- IEEE Electron Device Letters
- ISSN:
- 0741-3106
- Page Range / eLocation ID:
- 1 to 1
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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