arXiv subjects

Jiajie Cheng

Publications and source records attributed to Jiajie Cheng.

3 recordsLinked to original sources

arXiv2026

Qubit Noise Spectroscopy of Superconducting Dynamics in a Magnetic Field

An applied magnetic field affects a superconductor in two ways -- by promoting pairing fluctuations, and by inducing topological defects called vortices that carry quantized magnetic flux. A quantitative characterization of the resultant field-induced superconducting dynamics with spatio-temporal resolution remains challenging, particularly in two-dimensional materials. In this work, we analyze magnetic noise measured by the depolarization rate of a proximate single spin qubit as a non-invasive probe of such dynamical fluctuations. We demonstrate that the temperature dependence of the magnetic noise spectrum near $T_c$ deviates from predictions based on quasiparticle excitations due to critical superconducting fluctuations, which in turn are enhanced by a weak applied field. By analyzing the magnetic noise due to vortex dynamics, we further show that noise spectroscopy is not only able to distinguish between different vortex phases, but also extract key physical quantities of interest, such as oscillation frequencies of pinned vortices, phonon dispersion of vortex lattices and vortex diffusivity in a vortex liquid. Complementing recent work on noise magnetometry of quasiparticle excitations and Berezinskii-Kosterlitz-Thouless transitions in two-dimensional superconductors without an applied field, our work highlights the ability of noise spectroscopy to reveal a wealth of superconducting dynamical phenomena in an applied field.

cond-mat.supr-con↗

arXiv2025

HI-TransPA: Hearing Impairments Translation Personal Assistant

Hearing-impaired individuals often face significant barriers in daily communication due to the inherent challenges of producing clear speech. To address this, we introduce the Omni-Model paradigm into assistive technology and present HI-TransPA, an instruction-driven audio-visual personal assistant. The model fuses indistinct speech with lip dynamics, enabling both translation and dialogue within a single multimodal framework. To address the distinctive pronunciation patterns of hearing-impaired speech and the limited adaptability of existing models, we develop a multimodal preprocessing and curation pipeline that detects facial landmarks, stabilizes the lip region, and quantitatively evaluates sample quality. These quality scores guide a curriculum learning strategy that first trains on clean, high-confidence samples and progressively incorporates harder cases to strengthen model robustness. Architecturally, we employs a novel unified 3D-Resampler to efficiently encode the lip dynamics, which is critical for accurate interpretation. Experiments on purpose-built HI-Dialogue dataset show that HI-TransPA achieves state-of-the-art performance in both literal accuracy and semantic fidelity. Our work establishes a foundation for applying Omni-Models to assistive communication technology, providing an end-to-end modeling framework and essential processing tools for future research.

cs.CL↗

arXiv2025

Supply Chain Network Security Investment Strategies Based on Nonlinear Budget Constraints: The Moderating Roles of Market Share and Attack Risk

In the context of the rapid development of digital supply chain networks, dealing with the increasing cybersecurity threats and formulating effective security investment strategies to defend against cyberattack risks are the core issues in supply chain management. Cybersecurity investment decision-making is a key strategic task in enterprise supply chain manage-ment. Traditional game theory models and linear programming methods make it challenging to deal with complex problems such as multi-party par-ticipation in the supply chain, resource constraints, and risk uncertainty, re-sulting in enterprises facing high risks and uncertainties in the field of cy-bersecurity. To effectively meet this challenge, this study proposes a nonlin-ear budget-constrained cybersecurity investment optimization model based on variational inequality and projection shrinkage algorithm. This method simulates the impact of market competition on security investment by intro-ducing market share variables, combining variational inequality and projec-tion shrinkage algorithm to solve the model, and analyzing the effect of dif-ferent variables such as budget constraints, cyberattack losses, and market share on supply chain network security. In numerical analysis, the model achieved high cybersecurity levels of 0.96 and 0.95 in the experimental sce-narios of two retailers and two demand markets, respectively, and the budget constraint analysis revealed the profound impact of budget constraints on cybersecurity investment. Through numerical experiments and comparative analysis, the effectiveness and operability of this method in improving sup-ply chain network security are verified.

cs.CR↗