الجدران الخشنة تجعل الكيوبتات غير متوقعة سريع

الملخص الأصلي

كما كتبه المؤلفون، بالإنجليزية arXiv:2602.03037

As quantum processors scale to large qubit numbers, device-to-device variability emerges as a critical challenge. Superconducting qubits are commonly realized using Al/AlO$$_{\text{x}}$$/Al Josephson junctions operating in the tunneling regime, where even minor variations in device geometry can lead to substantial performance fluctuations. In this work, we develop a quantitative model for the variability of the Josephson energy $$E_{J}$$ induced by interface roughness at the Al/AlO$$_{\text{x}}$$ interfaces. The roughness is modeled as a Gaussian random field characterized by two parameters: the root-mean-square roughness amplitude $$\sigma $$ and the transverse correlation length $$\xi $$. These parameters are extracted from the literature and molecular dynamics simulations. Quantum transport is treated using the Ambegaokar--Baratoff relation combined with a local thickness approximation. Numerical simulations over $$5,000$$ Josephson junctions show that $$E_{J}$$ follows a log-normal distribution. The mean value of $$E_{J}$$ increases with $$\sigma $$ and decreases slightly with $$\xi $$, while the variance of $$E_{J}$$ increases with both $$\sigma $$ and $$\xi $$. These results paint a quantitative and intuitive picture of Josephson energy variability induced by surface roughness, with direct relevance for junction design.