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arXiv · 2510.22189

Effect of Stochastic Charge Noise in Si/SiGe Quantum-Dot Spin Qubits

Wei-en Chiu·Chia-Hsien Huang·Yi-Hsien Wu·Hsi-Sheng Goan
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Abstract

In Si/SiGe quantum dots, the decoherence behavior of spin qubits usually comes from the non-Markovian effect of the charge noise. To improve the performance of using the coherent noise models in the decoherence simulation and tomography analysis, here we propose a spin-phonon model derived from the electric dipole spin resonance to characterize the decoherence behavior of the spin qubit in a Si/SiGe quantum dot. Utilizing a 1/f spectrum to characterize quantum noise correlation, our stochastic model can yield a more precise prediction of decoherence compared to a random coherence model. We also use gate set tomography (GST) to address the error generator and analyze the model violation coming from the non-Markovian effect. Based on the results, we attribute certain error generators of this model to the incoherence error, which avoids the scenario of using too large a coherent noise strength in the previous study to account for the experimentally observed decoherence times, and thus underestimates the gate fidelity. We also perform a gate optimization and show that our optimized control pulse can substantially reduce the error contribution of the incoherent non-Markovian 1/f charge noise. We further demonstrate that the optimized pulse against incoherent noise is more robust against coherent noise than the regular Gaussian pulse through a filter function analysis in a CPMG protocol, demonstrating the significant effectiveness of the optimized pulse.

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Wei-en Chiu, Chia-Hsien Huang, Yi-Hsien Wu, Hsi-Sheng Goan. 2025-10-25. Effect of Stochastic Charge Noise in Si/SiGe Quantum-Dot Spin Qubits. https://arxiv.org/abs/2510.22189

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