arXiv subjects

Wei Su

Publications and source records attributed to Wei Su.

At least 19 recordsLinked to original sources

arXiv2026

A Synthetic Iterative Scheme for Non-Gray Phonon Boltzmann Transport Equation with Dual Relaxation Times

Solving the non-gray Callaway phonon Boltzmann transport equation allows a dual-relaxation-time approximation of separate normal and resistive scatterings and resolving the mode-dependent spectrum. The conventional iterative scheme (CIS) for deterministic solutions avoids a monolithic phase-space inversion, but its collision-source iteration can become prohibitively slow at a large characteristic length of a material. Existing synthetic acceleration schemes address either non-gray single-relaxation models or gray dual-relaxation models, leaving mode-resolved dual-relaxation transport without a dedicated acceleration framework. We develop a general synthetic iterative scheme (GSIS) for the stationary, linearized, non-gray Callaway equation, where synthetic approximations for the normal-process pseudo-temperature and phonon drift velocity are provided by exact energy and quasi-momentum balance laws closed with first-order Chapman-Enskog constitutive relations and non-equilibrium terms evaluated from the kinetic solution. The resistive-process pseudo-temperature is retrieved from the two quantities. Each iteration couples an upwind nodal discontinuous Galerkin kinetic sweep and a hybridizable discontinuous Galerkin solution of the synthetic equations to achieve high-order spatial discretization. A branch- and frequency-resolved Fourier analysis identifies the deterioration of CIS and shows that the GSIS contraction factor remains bounded away from unity for the considered graphene material. Asymptotic analysis indicates that GSIS reduces to a consistent discretization of a Guyer-Krumhansl-like equation and Fourier's law of heat conduction in the hydrodynamic and diffusive limits, respectively.

physics.comp-ph↗

arXiv2026

An asymptotic-preserving reduced-order method for parametrised rarefied gas flow by proper generalised decomposition

Modelling rarefied gas flow using the Boltzmann equation is vital in many areas. Due to the high dimensionality and coexistence of multiple characteristic scales, conventional solution strategies to this equation incur prohibitively high computational costs and are inadequate for rapid response in engineering design simulations. Based on proper generalised decomposition (PGD), we propose an \textit{a priori}, asymptotic-preserving reduced-order method to solve the high-dimensional, parametrised Shakhov kinetic model equation. The method reduces the original problem to a few low-dimensional problems by formulating separated representations for the low-rank solution, thereby mitigating the curse of dimensionality. To capture the hydrodynamic asymptotics, we incorporated solutions of some synthetic equations into the PGD algorithm. This treatment allows the PGD solver to automatically reduce to a macroscopic solver for the Navier-Stokes equations, whose solution naturally exhibits low-rank structure. By treating the rarefaction parameter as an additional coordinate, a parametrised solution can be computed once and for all over the entire range of rarefaction, enabling fast multiple queries to any points in the parameter space. Numerical examples are presented to demonstrate the capability of the method to simulate rarefied gas flow with certain accuracy and a significant reduction in computational costs.

math.NA↗

arXiv2026

Magnetic Cloud Boundary Identification Using a Local-Normalized Magnetic Field Parameter

Due to the lack of quantitative and reproducible criteria for identifying magnetic cloud (MC) boundaries, we propose a parameter that characterizes short-timescale variability in magnetic field strength. The parameter, referred to as the Local-Normalized Magnetic field parameter (LNM), is defined as $\mathrm{LNM}(t)=\log_{10}\left(B(t)/\langle B \rangle_{\mathrm{5m\text{-}med}}(t)\right)$, where $B(t)$ is the total magnetic field strength and $\langle B \rangle_{\mathrm{5m\text{-}med}}(t)$ is its 5-minute running median ending at time $t$. This parameter measures the deviation of the magnetic field magnitude from its local background and reveals a clear contrast between the coherent magnetic structure inside MCs and the more variable ambient solar wind. Based on this parameter, we develop a semi-automated method for MC boundary identification, supported by Time Series Scalogram visualization. We further analyze 76 MC events using power spectral density (PSD) and slab fraction diagnostics. The results show that the dissipation-range spectral index inside MCs ($\sim f^{-2.21}$) is systematically smaller than that outside ($\sim f^{-2.59}$ and $f^{-2.89}$), and the slab fraction is reduced, indicating suppressed small-scale variability and enhanced anisotropy. These results support the applicability of the proposed parameter for MC boundary identification.

physics.space-ph↗

arXiv2026

Probing the Electroweak Phase Transition in the Flipped Two-Higgs-Doublet Model at the LHC

We study the CP-conserving flipped (Type-Y) Two-Higgs-Doublet Model (2HDM) in the large-$\tan\beta$ regime ($\tan\beta>30$), focusing on its implications for electroweak phase transitions (EWPTs) and LHC phenomenology. Viable parameter regions supporting a strong first-order EWPT fall into two heavy-Higgs hierarchies: (A) $m_{H^\pm}\simeq m_H<m_A$ and (B) $m_H<m_{H^\pm} \simeq m_A$, both featuring a heaviest CP-odd Higgs $A$. Scenario~A typically proceeds via one-step transitions with lower nucleation temperatures, while Scenario~B allows one-step or two-step transitions, opening the decay $A\to H^\pm W^\mp$ and yielding richer collider signatures. In all cases, nucleation conditions are satisfied, avoiding false-vacuum trapping. We assess LHC prospects through bottom-associated production with multi-$b$ final states: $pp\to bbH\to 4b$ and $pp\to bbA\to bb W^\pm H^\mp\to 4b\ell\ell\nu\nu$. The $4b$ channel offers high-statistics discovery potential, reaching signal significances $z\gtrsim 25$ at the 13 TeV LHC with 300 fb$^{-1}$ and up to $z\gtrsim 100$ at the 14 TeV HL-LHC with 3 ab$^{-1}$. The cascade channel, while experimentally more challenging, directly probes the heavy Higgs spectrum and can discriminate between EWPT scenarios. Using optimized selections with a BDT-based multivariate analysis, significances of $z \simeq 6.8$ can be achieved in favorable regions of Scenario~B at the HL-LHC. These results indicate that the HL-LHC can realistically probe the BSM Higgs sector responsible for a strong first-order EWPT and provide insight into the underlying phase transition dynamics in the flipped 2HDM.

hep-ph↗

arXiv2026

The neutral scalars of type-II 2HDM+S under the LHC

The 2HDM+S is a singlet extension of the Two-Higgs-Doublet Model (2HDM), which offers rich collider phenomenology. In this paper, we parametrize the 2HDM+S with the Higgs masses and mixing angles, which provide a model-independent framework to study the collider signature. Under five benchmark scenarios, we obtain the 95\% C.L. exclusion regions in the Type-II 2HDM+S parameter space by incorporating the SM-like 125~GeV Higgs precision measurements, beyond the Standard Model Higgs direct searches, $Z$-pole precision measurements and $B$-physics observables. We present the results in the Higgs boson masses vs $\tan\beta$, Higgs boson masses vs mixing angles, $\tan\beta$ vs mixing angles and doublet Higgs boson masses vs singlet Higgs boson mass parameter space. We explore the complementarity between direct and indirect Higgs searches, as well as conventional Higgs search channels and exotic Higgs search channels. Compared to the 2HDM scenarios, we find that exotic channels such as $A/H \rightarrow Z h_S/ZA_S$ can probe large part of the parameter spaces, especially for moderate $1<\tan\beta<7$ region where the conventional channels in the 2HDM cannot contribute much.

hep-ph↗

arXiv2026

GI-Bench: A Panoramic Benchmark Revealing the Knowledge-Experience Dissociation of Multimodal Large Language Models in Gastrointestinal Endoscopy Against Clinical Standards

Multimodal Large Language Models (MLLMs) show promise in gastroenterology, yet their performance against comprehensive clinical workflows and human benchmarks remains unverified. To systematically evaluate state-of-the-art MLLMs across a panoramic gastrointestinal endoscopy workflow and determine their clinical utility compared with human endoscopists. We constructed GI-Bench, a benchmark encompassing 20 fine-grained lesion categories. Twelve MLLMs were evaluated across a five-stage clinical workflow: anatomical localization, lesion identification, diagnosis, findings description, and management. Model performance was benchmarked against three junior endoscopists and three residency trainees using Macro-F1, mean Intersection-over-Union (mIoU), and multi-dimensional Likert scale. Gemini-3-Pro achieved state-of-the-art performance. In diagnostic reasoning, top-tier models (Macro-F1 0.641) outperformed trainees (0.492) and rivaled junior endoscopists (0.727; p>0.05). However, a critical "spatial grounding bottleneck" persisted; human lesion localization (mIoU >0.506) significantly outperformed the best model (0.345; p<0.05). Furthermore, qualitative analysis revealed a "fluency-accuracy paradox": models generated reports with superior linguistic readability compared with humans (p<0.05) but exhibited significantly lower factual correctness (p<0.05) due to "over-interpretation" and hallucination of visual features. GI-Bench maintains a dynamic leaderboard that tracks the evolving performance of MLLMs in clinical endoscopy. The current rankings and benchmark results are available at https://roterdl.github.io/GIBench/.

cs.CV↗

arXiv2026

Accelerated simulation of multiscale gas-radiation coupling flows via a general synthetic iterative scheme

Gas-radiation coupling critically influences hypersonic reentry flows, where extreme temperatures induce pronounced non-equilibrium gas and radiative heat transport. Accurate and efficient simulation of radiative gas dynamics is therefore indispensable for reliable design of thermal protection systems for atmospheric entry vehicles. In this study, a Boltzmann-type kinetic model for radiative gas flows is solved across a broad spectrum of flow and radiation transport regimes using the general synthetic iterative scheme (GSIS). The approach integrates an unstructured finite-volume discrete velocity method with a set of macroscopic synthetic equations. Within this framework, the kinetic model provides high-order closures for the constitutive relations in the synthetic equations. Simultaneously, the macroscopic synthetic equations drive the evolution of the mesoscopic kinetic system, significantly accelerating steady-state convergence in near-continuum regimes, as substantiated by linear Fourier stability analysis. Crucially, the algorithm is proven to be asymptotic-preserving, correctly recovering the continuum and optically thick limits, represented by the radiative Navier-Stokes-Fourier equations governing distinct translational, rotational, vibrational, and radiative temperatures, on coarse meshes independent of the mean free path. Numerical simulations of challenging benchmarks, including three-dimensional hypersonic flow over an Apollo reentry capsule, demonstrate that GSIS achieves orders-of-magnitude speedup over conventional iterative schemes in multiscale simulations of radiative gas flows while accurately capturing non-equilibrium effects and radiative heat transfer in hypersonic environments.

physics.comp-ph↗

arXiv2025

Probing compressed Higgsinos at the FASER experiment

In the Minimal Supersymmetric Standard Model (MSSM), compressed Higgsinos spectrum ($\Delta m^0 \lesssim 1$ GeV) occurs when $|\mu| \ll |M_1|, |M_2|$ and ${\rm sign}(M_1\cdot M_2)<0$, which leads to a long-lived next-to-lightest neutralino. Such a long-lived neutralino could be copiously produced at the LHC, however escape the detection at the LHC main detectors. We examine the discovery potential at the FASER experiment and find that the FASER 2 could cover the neutral Higgsino mass up to about 130 GeV with mass splitting between 4 to 30 MeV. It is complementary to both the LHC Higgsino search in the $\Delta m^{0,\pm} \gtrsim 1$ GeV region, and displaced vertex and disappearing track searches of charginos with $\Delta m^\pm \lesssim 1$ GeV.

hep-ph↗

arXiv2025

Search for Light Neutral Scalar in the Georgi-Machacek Model with Forward Detectors at the LHC

Long-lived particle (LLP) is one of the well-motivated targets for current collider experiments searching for the physics beyond the Standard Model. In recent years, many dedicated detectors have been developed for such scenarios which are designed to extend the sensitivity to weakly coupled particles with macroscopic $c\tau$. In this work, we investigate the LLP signatures of the neutral component of the fermiophobic fiveplet $H_5^0$ in the Georgi-Machacek model. Due to its fermiophobic nature at tree level, it possesses suppressed decay widths in the low mass region and can naturally be long-lived over a wide region of parameter space. We show that $H_5^0$ can be produced with an appreciable flux in the forward region from the meson decay through loop-induced couplings leading to observable LLP signatures in forward detectors. We evaluate the sensitivity of representative forward detectors to this scenario and compare the result with existing constraints from terrestrial experiments and astrophysical observations. Our results demonstrate that the forward detectors can probe the $s_H$ down to $\mathcal{O}(10^{-5})$ for sub-GeV scalar masses, and hence providing a powerful and complementary probe of the extended Higgs sectors that is inaccessible to conventional searches.

hep-ph↗

arXiv2025

Global fits and the search for new physics: past, present and future

In this work, we review the history and current role of global fits in the search for physics beyond the Standard Model~(BSM), including precision tests of the Standard Model (SM). Although BSM global fits were initially focused on minimal supersymmetric models, we describe how fits have evolved in response to new data from the Large Hadron Collider (LHC) and elsewhere, expanding to encompass a broad spectrum of BSM scenarios including non-minimal supersymmetry, axion-like particles, extended Higgs sectors, dark matter models, and effective field theories such as SMEFT. We discuss how the role of global fits has shifted from forecasting possible signals of new physics at the LHC to understanding the impact of null results from LHC run-I and II and the discovery of the Higgs boson, and how interest has shifted from global fits for parameter estimation to comprehensive model comparison. We close by discussing potential trends and future applications, emphasizing the potential for machine learning and artificial intelligence to enhance the efficiency of sampling algorithms and comparison between theory and experiment, as well as collaboration and software development.

hep-ph↗

arXiv2025

Formation and Evolution of the Spin-Charge-Entangled Screening Cloud in the Majorana-Kondo System

Side-coupled Majorana zero modes in Kondo systems realize a simple yet nontrivial hybridization setup that leads to distinct physics from the conventional Kondo effect. We have demonstrated in a previous work that the system can be described by a spin-charge-entangled (SCE) quantum impurity model with an Andreev$\otimes$normal boundary condition. Here we investigate in detail the formation process and microscopic mechanism of the SCE screening cloud using the numerical renormalization group method. We introduce temperature-dependent spatially integrated correlation functions that provide an unambiguous diagnostic of different components of the SCE screening cloud beyond the impurity entropy and local density of states. Our results reveal a crossover from a sequential two-stage screening of the spin and charge components to a simultaneous screening controlled by a single parameter. We also study the evolution of the low-energy fixed points in the presence of competing terms that break different symmetries and drive the system to different infrared fixed points. Our results suggest that the SCE screening effect in the Majorana-Kondo system makes itself a route to detecting Majorana zero modes.

cond-mat.str-el↗

arXiv2025

The Impact of Solar-Terrestrial Plasma and Magnetic Field on the Detection of Space-borne Gravitational Wave Detections

Space-borne gravitational wave detections raise new questions for heliophysics: how the Sun-Terrestrial space environment affect gravitational wave detection, and to what extent? Space-borne gravitational wave detectors use laser interferometry to measure displacement variations between two free test masses caused by gravitational waves. Space-borne gravitational wave detectors require extremely high measurement accuracy, making it necessary to take into account the effects of space plasma and magnetic field. On one hand, laser propagation through space plasma can induce optical path difference noise, affecting distance measurement accuracy. On the other hand, interactions between space magnetic field and the test masses can generate acceleration noise. This review introduces studies on laser propagation noise and space magnetic acceleration noise in space gravitational wave detection. And this review presents a method, time-delay interferometry, to suppress laser propagation noise.

astro-ph.SR↗

arXiv2025

Complete Light Long-Lived Particles searches in Type-I 2HDM

Recently, the study of long-lived particles (LLPs) has attracted increasing attention. In this work, we analyze the full parameter space of the Type-I Two-Higgs-Doublet Model (2HDM) that allows for light long-lived scalar ($H$) and pseudoscalar ($A$) particles. When involving a light beyongd Standard Model (BSM) Higgs, the $\Delta S$ could be the main contribution during the global fit of the oblique parameters, which is different to $\Delta T$ being the main factor for heavy BSM Higgs cases. By imposing theoretical constraints such as vacuum stability and perturbative unitarity, together with current experimental bounds, we summarize a complete region for a potential light $H$ with $\cos(\beta - \alpha) \simeq \frac{1}{\tan \beta}$, light $A$ with $\cos(\beta - \alpha) \simeq \frac{1}{\tan\beta} \frac{2m_H^2 - m_h^2}{m_H^2 - m_h^2}$, and point out the invisible Higgs decay is the most important constraint. We further identify viable regions for LLPs and propose four benchmark regions that simultaneously accommodate a light long-lived particle and explain the $W$ boson mass anomaly. For these benchmarks, we present the reaches of FASER and FASER~2, where FASER~2 improves the sensitivity by approximately two orders of magnitude compared to FASER.

hep-ph↗

arXiv2025

Dynamic-DINO: Fine-Grained Mixture of Experts Tuning for Real-time Open-Vocabulary Object Detection

The Mixture of Experts (MoE) architecture has excelled in Large Vision-Language Models (LVLMs), yet its potential in real-time open-vocabulary object detectors, which also leverage large-scale vision-language datasets but smaller models, remains unexplored. This work investigates this domain, revealing intriguing insights. In the shallow layers, experts tend to cooperate with diverse peers to expand the search space. While in the deeper layers, fixed collaborative structures emerge, where each expert maintains 2-3 fixed partners and distinct expert combinations are specialized in processing specific patterns. Concretely, we propose Dynamic-DINO, which extends Grounding DINO 1.5 Edge from a dense model to a dynamic inference framework via an efficient MoE-Tuning strategy. Additionally, we design a granularity decomposition mechanism to decompose the Feed-Forward Network (FFN) of base model into multiple smaller expert networks, expanding the subnet search space. To prevent performance degradation at the start of fine-tuning, we further propose a pre-trained weight allocation strategy for the experts, coupled with a specific router initialization. During inference, only the input-relevant experts are activated to form a compact subnet. Experiments show that, pretrained with merely 1.56M open-source data, Dynamic-DINO outperforms Grounding DINO 1.5 Edge, pretrained on the private Grounding20M dataset.

cs.CV↗

arXiv2025

The electroweak precision constraints of the 2HDM+S

The 2HDM+S is the singlet extension of the Two-Higgs-Doublets Model (2HDM). The singlet field and its mixing with the 2HDM Higgs sector lead to new contributions to the electroweak precision observables, in particular, the oblique parameters. In this paper, we identify five benchmark cases, where at most one mixing angle is nonzero and analyze the 95% C.L. allowed parameter space by the oblique parameters. In the alignment limit of the 2HDM, we find that other than the usual mass relations of $m_H\sim m_{H^\pm}$ or $m_A\sim m_{H^\pm}$, electroweak precision measurements also impose an upper limit on the neutral Higgs masses. In the cases with nonzero singlet mixing with the 2HDM Higgses $H$ or $A$, we find approximate mass relations of $c^2_{\alpha_{HS}} m_{H} + s^2_{\alpha_{HS}}m_{h_S} = m_{H^\pm}$ or $c^2_{\alpha_{AS}} m_{A} + s^2_{\alpha_{AS}}m_{A_S} = m_{H^\pm}$. Those relations are universal to the 2HDM+S models, with or without further symmetry assumption. We also study the non-alignment limit of the 2HDM+S, which typically has tighter constraints on the masses and mixing angles. At the end, we examine the complementarity between the electroweak precision analyses and the Higgs coupling precision measurements.

hep-ph↗

arXiv2025

Properties of Quasi-synchronization Time of High-dimensional Hegselmann-Krause Dynamics

The behavior of one-dimensional Hegselmann-Krause (HK) dynamics driven by noise has been extensively studied. Previous research has indicated that within no matter the bounded or the unbounded space of one dimension, the HK dynamics attain quasi-synchronization (synchronization in noisy case) in finite time. However, it remains unclear whether this phenomenon holds in high-dimensional space. This paper investigates the random time for quasi-synchronization of multi-dimensional HK model and reveals that the boundedness and dimensions of the space determine different outcomes. To be specific, if the space is bounded, quasi-synchronization can be attained almost surely for all dimensions within a finite time, whereas in unbounded space, quasi-synchronization can only be achieved in low-dimensional cases (one and two). Furthermore, different integrability of the random time of various cases is proved.

math.DS↗

arXiv2025

Memory-Driven Bounded Confidence Opinion Dynamics: A Hegselmann-Krause Model Based on Fractional-Order Methods

Memory effects play a crucial role in social interactions and decision-making processes. This paper proposes a novel fractional-order bounded confidence opinion dynamics model to characterize the memory effects in system states. Building upon the Hegselmann-Krause framework and fractional-order difference, a comprehensive model is established that captures the persistent influence of historical information. Through rigorous theoretical analysis, the fundamental properties including convergence and consensus is investigated. The results demonstrate that the proposed model not only maintains favorable convergence and consensus characteristics compared to classical opinion dynamics, but also addresses limitations such as the monotonicity of bounded opinions. This enables a more realistic representation of opinion evolution in real-world scenarios. The findings of this study provide new insights and methodological approaches for understanding opinion formation and evolution, offering both theoretical significance and practical applications.

physics.soc-ph↗

arXiv2025

Reduced-Order Solution for Rarefied Gas Flow by Proper Generalised Decomposition

Modelling rarefied gas flow via the Boltzmann equation plays a vital role in many areas. Due to the high dimensionality of this kinetic equation and the coexistence of multiple characteristic scales in the transport processes, conventional solution strategies incur prohibitively high computational costs and are inadequate for rapid response for parametric analysis and optimisation loops in engineering design simulations. This paper proposes an \textit{a priori} reduced-order method based on the proper generalised decomposition to solve the high-dimensional, parametrised Shakhov kinetic model equation. This method reduces the original problem into a few low-dimensional problem by formulating separated representations for the low-rank solution, as well as data and operators in the equation, thereby overcoming the curse of dimensionality. Furthermore, a general solution can be calculated once and for all in the whole range of the rarefaction parameter, enabling fast and multiple queries to a specific solution at any point in the parameter space. Numerical examples are presented to demonstrate the capability of the method to simulate rarefied gas flow with high accuracy and significant reduction in CPU time and memory requirements.

math.NA↗