arXiv subjects

Qi Huang

Publications and source records attributed to Qi Huang.

At least 73 records · Page 4Linked to original sources

arXiv2024

Cohort profile: the Northwest China Real-world and Population-based Cohort

The Northwest China Real-World and Population-based cohort is an ongoing prospective cohort with more than 25 million population, covering almost all residents across approximately 1.66 million square kilometers in northwest China; The cohort integrates data from various sources, including health profiles, examination records, electronic health records, mortality records, statistical yearbooks, and environmental datasets, covering comprehensive health-related factors such as demographics, lifestyle factors, family medical history, living conditions, enrollment in national public health services, physical examinations, blood assay tests, diagnostic assessments, disease outcomes, and cause-specific mortality. This real-world dataset can evaluate clinical treatment effectiveness and prognosis, assess impact of health policy, and investigate the health effects of multiple risk factors . From January 2019 to December 2023, the cohort has included 13,634,481 participants, accumulating 47,050,707 person-years of follow-up, with 13,598,407 medical diagnosis records and 881,114 recorded deaths. Cohort data are available upon request. De-identified and anonymized data are stored on local servers and accessed through a data-sharing platform, enabling users to utilize the data without direct access to the raw information. A description of the proposed research can be sent to Yining Yang & Qian Di.

cs.CY↗

arXiv2024

TX-Gen: Multi-Objective Optimization for Sparse Counterfactual Explanations for Time-Series Classification

In time-series classification, understanding model decisions is crucial for their application in high-stakes domains such as healthcare and finance. Counterfactual explanations, which provide insights by presenting alternative inputs that change model predictions, offer a promising solution. However, existing methods for generating counterfactual explanations for time-series data often struggle with balancing key objectives like proximity, sparsity, and validity. In this paper, we introduce TX-Gen, a novel algorithm for generating counterfactual explanations based on the Non-dominated Sorting Genetic Algorithm II (NSGA-II). TX-Gen leverages evolutionary multi-objective optimization to find a diverse set of counterfactuals that are both sparse and valid, while maintaining minimal dissimilarity to the original time series. By incorporating a flexible reference-guided mechanism, our method improves the plausibility and interpretability of the counterfactuals without relying on predefined assumptions. Extensive experiments on benchmark datasets demonstrate that TX-Gen outperforms existing methods in generating high-quality counterfactuals, making time-series models more transparent and interpretable.

cs.LG↗

arXiv2024

Bell state generation and CNOT operation using on-demand identical photons from shape-controlled spatially ordered quantum dots

Fault tolerant on-chip photonic quantum computation is enormously helped by (a) deterministic generation of the needed thousands to millions of photon qubits from (b) quantum emitters in designed spatially ordered arrays to enable networks for implementing many-qubit logic circuits. Scaling up photonic quantum information processing systems has, however, been prevented by the lack of such quantum emitters until the demonstration of the platform of mesa-top single quantum dots (MTSQDs) -- controlled shape, size, and volume single QD -- located in designed regular arrays. Here we demonstrate 2 qubit CNOT gate operation -- a universal gate necessary to enable quantum circuits of arbitrary complexity -- in polarization basis using photons emitted from individual MTSQDs. A Bell state fidelity of 0.825$\pm$0.010 is achieved with two photon interference (TPI) visibility of 0.947$\pm$0.0015 at 4K without Purcell enhancement. The results make a strong case for developing MTSQD arrays for utility scale optical quantum information processing platforms.

quant-ph↗

arXiv2024

Divergence of thermalization rates driven by the competition between finite temperature and quantum coherence

The thermalization of an isolated quantum system is described by quantum mechanics and thermodynamics, while these two subjects are still not fully consistent with each other. This leaves a less-explored region where both quantum and thermal effects cannot be neglected, and the ultracold atom platform provides a suitable and versatile testbed to experimentally investigate these complex phenomena. Here we perform experiments based on ultracold atoms in optical lattices and observe a divergence of thermalization rates of quantum matters when the temperature approaches zero. By ramping an external parameter in the Hamiltonian, we observe the time delay between the internal relaxation and the external ramping. This provides us with a direct comparison of the thermalization rates of different quantum phases. We find that the quantum coherence and bosonic stimulation of superfluid induces the divergence while the finite temperature and the many-body interactions are suppressing the divergence. The quantum coherence and the thermal effects are competing with each other in this isolated thermal quantum system, which leads to the transition of thermalization rate from divergence to convergence.

cond-mat.quant-gas↗

arXiv2024

$X_0(2900)$ and $χ_{c0}(3930)$ in process $B^+\to D^+ D^- K^+$

This study investigates the nature of the $X_0(2900)$ and $χ_{c0}(3930)$ based on experimental results of the process $B^+$$\to$$D^+ D^- K^+$. We focus on the S-wave $D^{*-}K^{*+}$ and $D_s^+D_s^-$ molecular states, which can be related to the $X_0(2900)$ and $χ_{c0}(3930)$, respectively. Using effective Lagrangians, we construct the potential kernel of the $D^{*-}K^{*+}$$-$$D^{-}K^{+}$ and $D_s^+D_s^-$$-$$D^+D^-$ interactions with a one-boson-exchange model, and determine the scattering amplitudes and their poles through a quasipotential Bethe-Salpeter equation approach. By incorporating the potential kernel into the three-body decay process $B^+$$\to$$D^+ D^- K^+$, we evaluate the $D^-K^+$ and $D^+D^-$ invariant mass spectra, as well as the Dalitz plot, with Monte Carlo simulation. A satisfactory fit to the $D^-K^+$ and $D^+D^-$ invariant mass spectra is achieved after introducing additional Breit-Wigner resonances, the $X_1(2900)$, $ψ(3770)$, and $χ_{c2}(3930)$ states. Prominent signals of the $X_0(2900)$ and $χ_{c0}(3930)$ states appear as peaks in the $D^-K^+$ and $D^+D^-$ invariant mass spectra near 2900 and 3930 MeV, respectively. Clear event concentration of the $X_0(2900)$ and $χ_0(3930)$ states is evident as strips in the Dalitz plot. The results suggest that both $X_0(2900)$ and $χ_{c0}(3930)$ can be interpreted as molecular states, with the inclusion of $X_1(2900)$ and $χ_2(3930)$ necessary to describe structures in the regions near 2900 and 3930 MeV.

hep-ph↗

arXiv2024

Latent Conditional Diffusion-based Data Augmentation for Continuous-Time Dynamic Graph Model

Continuous-Time Dynamic Graph (CTDG) precisely models evolving real-world relationships, drawing heightened interest in dynamic graph learning across academia and industry. However, existing CTDG models encounter challenges stemming from noise and limited historical data. Graph Data Augmentation (GDA) emerges as a critical solution, yet current approaches primarily focus on static graphs and struggle to effectively address the dynamics inherent in CTDGs. Moreover, these methods often demand substantial domain expertise for parameter tuning and lack theoretical guarantees for augmentation efficacy. To address these issues, we propose Conda, a novel latent diffusion-based GDA method tailored for CTDGs. Conda features a sandwich-like architecture, incorporating a Variational Auto-Encoder (VAE) and a conditional diffusion model, aimed at generating enhanced historical neighbor embeddings for target nodes. Unlike conventional diffusion models trained on entire graphs via pre-training, Conda requires historical neighbor sequence embeddings of target nodes for training, thus facilitating more targeted augmentation. We integrate Conda into the CTDG model and adopt an alternating training strategy to optimize performance. Extensive experimentation across six widely used real-world datasets showcases the consistent performance improvement of our approach, particularly in scenarios with limited historical data.

cs.LG↗

arXiv2024

Retiming dynamics of harmonically modelocked laser solitons in a self-driven optomechanical lattice

Harmonic mode-locking, realized actively or passively, is an effective technique for increasing the repetition rate of lasers, with important applications in optical sampling, laser micro-machining and frequency metrology. It is critically important to understand how a harmonically mode-locked pulse train responds to external perturbations and noise, so as to make sure that it is stable and resistant to noise. Here, in a series of carefully designed experiments, we elucidate the retiming dynamics of laser pulses generated in a soliton fiber laser harmonically mode-locked at ~2 GHz to the acoustic resonance in a photonic crystal fiber (PCF) core. We characterize the self-driven optomechanical lattice along the PCF using a homodyne set-up, and reveal that each soliton undergoes damped oscillatory retiming within its trapping potential after an abrupt perturbation. In addition we show, through statistical analysis of the intra-cavity pulse spacing, how the trapping potentials are effective for suppressing timing jitter. The experimental results are well described using a dynamic model including dissipation, which provides valuable insight into the stability and noise performance of optomechanically mode-locked laser systems, and may also be useful for studying complex inter-soliton interactions.

physics.optics↗

arXiv2024

The role of triangle singularity in isospin breaking process $J/ψ\to Λ\barΛ π$ and the possible evidence of $Σ^*(\frac{1}{2}^-)$ states

In this study, the impact of triangle singularity is investigated in the isospin-breaking process $J/ψ\to Λ\barΛ π$. The triangle singularity is found to play a significant role in the process, resulting in the creation of a resonance-like structure around 1.4 GeV in the $Λπ(\barΛπ)$ invariant mass spectrum. To amplify the impact of this triangle singularity, the presence of two $Σ^*(\frac{1}{2}^-)$ states around 1.4 GeV and 1.6 GeV is essential, yet these states have not been definitively identified in the current baryon spectrum. We recommend that experiments, particularly the Beijing Spectrometer (BESIII) and the future Super Tau-Charm Factory (STCF), to investigate the process $J/ψ\to Λ\barΛ π$ to offer direct evidences for our predicted triangle singularity and additional evidence regarding the $Σ(\frac{1}{2}^-)$ states.

hep-ph↗

arXiv2024

Investigating $Ξ$ resonances from pentaquark perspective

We have investigated the $qss\bar{q}q$ ($q = u$ or $d$) system to find possible pentaquark explanations for the $Ξ$ resonances. The bound state calculation is carried out within the framework of the quark delocalization color screening model. The scattering processes are also studied to examine the possible resonance states. The current results indicate that the $Ξ(1950)$ can be interpreted as $Λ\bar{K}^*$ state with $J^P = 1/2^-$. Three states are identified that match the $Ξ(2250)$, which are $Σ^* \bar{K}^*$ state with $J^P = 3/2^-$, $Σ^* \bar{K}^*$ state with $J^P =5/2^-$, and $Ξ^* ρ$ state with $J^P =5/2^-$. This may explain the conflicting experimental values for the width of the $Ξ(2250)$. A new $Ξ$ resonance is predicted, whose mass and width are 2066--2079 MeV and 186--189 MeV, respectively. These results contribute to understanding the nature of the $Ξ$ resonances and to the future search for new $Ξ$ resonances. Moreover, it is meaningful to further investigate the $Ξ$ resonances from an unquenched picture on the basis of pentaquark investigation.

hep-ph↗

arXiv2024

Blockchain for Energy Market: A Comprehensive Survey

The energy market encompasses the behavior of energy supply and trading within a platform system. By utilizing centralized or distributed trading, energy can be effectively managed and distributed across different regions, thereby achieving market equilibrium and satisfying both producers and consumers. However, recent years have presented unprecedented challenges and difficulties for the development of the energy market. These challenges include regional energy imbalances, volatile energy pricing, high computing costs, and issues related to transaction information disclosure. Researchers widely acknowledge that the security features of blockchain technology can enhance the efficiency of energy transactions and establish the fundamental stability and robustness of the energy market. This type of blockchain-enabled energy market is commonly referred to as an energy blockchain. Currently, there is a burgeoning amount of research in this field, encompassing algorithm design, framework construction, and practical application. It is crucial to organize and compare these research efforts to facilitate the further advancement of energy blockchain. This survey aims to comprehensively review the fundamental characteristics of blockchain and energy markets, highlighting the significant advantages of combining the two. Moreover, based on existing research outcomes, we will categorize and compare the current energy market research supported by blockchain in terms of algorithm design, market framework construction, and the policies and practical applications adopted by different countries. Finally, we will address current issues and propose potential future directions for improvement, to provide guidance for the practical implementation of blockchain in the energy market.

cs.NI↗

arXiv2024

MegaScale: Scaling Large Language Model Training to More Than 10,000 GPUs

We present the design, implementation and engineering experience in building and deploying MegaScale, a production system for training large language models (LLMs) at the scale of more than 10,000 GPUs. Training LLMs at this scale brings unprecedented challenges to training efficiency and stability. We take a full-stack approach that co-designs the algorithmic and system components across model block and optimizer design, computation and communication overlapping, operator optimization, data pipeline, and network performance tuning. Maintaining high efficiency throughout the training process (i.e., stability) is an important consideration in production given the long extent of LLM training jobs. Many hard stability issues only emerge at large scale, and in-depth observability is the key to address them. We develop a set of diagnosis tools to monitor system components and events deep in the stack, identify root causes, and derive effective techniques to achieve fault tolerance and mitigate stragglers. MegaScale achieves 55.2% Model FLOPs Utilization (MFU) when training a 175B LLM model on 12,288 GPUs, improving the MFU by 1.34x compared to Megatron-LM. We share our operational experience in identifying and fixing failures and stragglers. We hope by articulating the problems and sharing our experience from a systems perspective, this work can inspire future LLM systems research.

cs.LG↗

arXiv2024

Shapelet-based Model-agnostic Counterfactual Local Explanations for Time Series Classification

In this work, we propose a model-agnostic instance-based post-hoc explainability method for time series classification. The proposed algorithm, namely Time-CF, leverages shapelets and TimeGAN to provide counterfactual explanations for arbitrary time series classifiers. We validate the proposed method on several real-world univariate time series classification tasks from the UCR Time Series Archive. The results indicate that the counterfactual instances generated by Time-CF when compared to state-of-the-art methods, demonstrate better performance in terms of four explainability metrics: closeness, sensibility, plausibility, and sparsity.

cs.LG↗

arXiv2024

KS-Net: Multi-band joint speech restoration and enhancement network for 2024 ICASSP SSI Challenge

This paper presents the speech restoration and enhancement system created by the 1024K team for the ICASSP 2024 Speech Signal Improvement (SSI) Challenge. Our system consists of a generative adversarial network (GAN) in complex-domain for speech restoration and a fine-grained multi-band fusion module for speech enhancement. In the blind test set of SSI, the proposed system achieves an overall mean opinion score (MOS) of 3.49 based on ITU-T P.804 and a Word Accuracy Rate (WAcc) of 0.78 for the real-time track, as well as an overall P.804 MOS of 3.43 and a WAcc of 0.78 for the non-real-time track, ranking 1st in both tracks.

cs.SD↗

arXiv2023

Large-Area Spatially Ordered Mesa Top Single Quantum Dots: Suitable Single Photon Emitters for On-Chip Integrated Quantum Information Processing Platforms

Realization of the long sought on-chip scalable photonic quantum information processing networks has been thwarted by the absence of spatially-ordered and scalable on-demand single photon emitters with emission figures-of-merit exceeding the required thresholds across large numbers. The positioning must meet the required degree of accuracy that enables fabricating their interconnection to create the desired functional network. Here we report on the realization of large-area spatially-ordered arrays of mesa-top single quantum dots (MTSQDs) that are demonstrated [1] to be on-demand single photon emitters with characteristics that meet the requirements for implementing quantum photonic circuits/platforms aimed at quantum key distribution, linear optical quantum computing, simulations of quantum many-body problems, and metrology/sensing. The reported GaAs/InGaAs/GaAs MTSQD arrays, grown via SESRE (substrate-encoded size-reducing epitaxy) are in multiple arrays of up to 100x100 with 5um pitch, across a centimeter radius area. We show illustrative large-area images of the emission intensity (brightness) and color-coded wavelength distribution exhibiting ~3.35nm standard deviation. Scanning transmission electron microscopy shows a remarkable control on the QD location to within ~3nm accuracy laterally and ~1nm vertically. The primary remaining challenge is the control on the uniformity of the currently wet-chemically etched as-patterned nanomesa lateral size across the substrate, a surmountable technical issue. Thus, SESRE offers the most promising approach to realizing on-chip scalable spatially-ordered arrays of on-demand bright single quantum emitters meeting the figures-of-merit required for on-chip fully integrated quantum photonic circuit platforms-monolithic (such as based upon AlGaAs on insulator) or hybrid that leverage the silicon-on-insulator (SOI) photonic integrated circuit (PIC).

quant-ph↗

arXiv2023

BAE-Net: A Low complexity and high fidelity Bandwidth-Adaptive neural network for speech super-resolution

Speech bandwidth extension (BWE) has demonstrated promising performance in enhancing the perceptual speech quality in real communication systems. Most existing BWE researches primarily focus on fixed upsampling ratios, disregarding the fact that the effective bandwidth of captured audio may fluctuate frequently due to various capturing devices and transmission conditions. In this paper, we propose a novel streaming adaptive bandwidth extension solution dubbed BAE-Net, which is suitable to handle the low-resolution speech with unknown and varying effective bandwidth. To address the challenges of recovering both the high-frequency magnitude and phase speech content blindly, we devise a dual-stream architecture that incorporates the magnitude inpainting and phase refinement. For potential applications on edge devices, this paper also introduces BAE-NET-lite, which is a lightweight, streaming and efficient framework. Quantitative results demonstrate the superiority of BAE-Net in terms of both performance and computational efficiency when compared with existing state-of-the-art BWE methods.

cs.SD↗

arXiv2023

Charmoniumlike resonant explanation on the newly observed $X(3960)$

Stimulated by the observation of the newly $X(3960)$ observed by the LHCb collaboration, we adopt the one-boson-exchange model and consider the $S-D$ wave mixing effects to study the $D_s\bar{D}_s/D^*\bar{D}^*/D_s^*\bar{D}_s^*$ interactions with $I(J^{PC})=0(0^{++})$. After producing the phase shifts of this coupled channel systems, our results show that there can exist a charmoniumlike resonance, whose obtained mass and width can both well match with the experimental data of the newly observed $X(3960)$. We also find that the $D^*\bar{D}^*$ system plays an important role in the formation of the newly observed $X(3960)$ as a charmoniumlike resonance, and the $D_s^*\bar{D}_s^*$ system makes a significant contribution to the resonant width. As a byproduct, we perform a coupled channel analysis on the $D^*\bar{D}^*/D_s\bar{D}_s^*/D_s^*\bar{D}_s^*$ interactions with $I(J^{PC})=0(1^{+-})$, our results can predict the existence of the $D_s\bar{D}_s^*$ molecule with $1^{+-}$ and the $D_s^*\bar{D}_s^*$ molecule with $1^{+-}$. Their widths are around several and several to several tens MeV, respectively. Experimental searches for these two possible charmoniumlike molecular candidates can be helpful to verify our proposal.

hep-ph↗

arXiv2023

Possible open charm molecular pentaquarks from $Λ_cK^{()}/Σ_cK^{()}$ interactions

In this work, we adopt the one-boson-exchange model to study the $Y_cK^{(*)} (Y_c=Λ_c, Σ_c)$ interactions. After considering both of the $S-D$ wave mixing effects and the coupled channel effects, we can predict several possible open-charm molecular pentaquarks, i.e., the single $Σ_cK^*$ molecular states with $I(J^P)=1/2(1/2^-)$, $1/2(3/2^-)$ and $3/2(1/2^-)$, the coupled $Λ_cK^*/Σ_cK^*$ molecular states with $1/2(1/2^-)$ and $1/2(3/2^-)$, and the coupled $Σ_cK/Λ_cK^*/Σ_cK^*$ molecular state with $1/2(1/2^-)$. Meanwhile, we extend our study to the $Y_c\bar{K}^{(*)}$ interactions, our results suggest the $Σ_c\bar{K}$ system with $I(J^P)=1/2(1/2^-)$, the $Σ_c\bar{K}^*$ systems with $1/2(1/2^-)$, $1/2(3/2^-)$, and $3/2(3/2^-)$, the coupled $Λ_c\bar{K}^*/Σ_c\bar K^*$ system with $1/2(1/2^-)$, and the $Σ_c\bar{K}/Λ_c\bar{K}^*/Σ_c\bar K^*$ system with $1/2(1/2^-)$ can be the prime molecular candidates.

hep-ph↗

arXiv2023

Soliton Blockade for Nonlinear Accelerating Pulses

We study the nonlinear propagation of truncated Airyprime pulses in optical fibers with both anomalous or normal dispersion. Weobservenonlinear self-accelerating pulses with notable red-shifted spectral notch (double peaks) or blue-shifted spectral peak depending on whether the dispersion is anomalous or normal. SuchprocessisinsharpcontrasttothatofAirypulses.The formation of nonlinear self-accelerating pulses is very sensitive to the truncated coefficient. The relationship between the characteristics of such accelerated pulses and the truncated coefficient are disclosed and compared in detail. Our results not only shed new light on the nonlinear propagation of Airyprime pulses, but also provide a novel method to generate nonlinear self-accelerating pulses as well as enable the realization of very efficient wavelength conversion based on the controlled frequency shift. Based on space-time duality, self-accelerating spatiotemporal nonlinear light bullets can be envisaged from the propagation of spatiotemporal Airyprime wave packets in pure Kerr medium.

physics.optics↗