arXiv subjects

Qi Huang

Publications and source records attributed to Qi Huang.

108 records · Page 6Linked to original sources

arXiv2021

Study of form factors and branching ratios for $D\rightarrow S,Al\bar{ν_{l}}$ with light-cone sum rules

We systematically study the semileptonic decay process of $ D\rightarrow S,A l\bar{ν_{l}}(l=e,μ)$ by light-cone sum rules (LCSR) with chiral currents, calculate the form factors containing only the contribution of the leading twist light-cone distribution amplitudes (LCDAs). For scalar mesons $a_{0}(980)$ and $a_{0}(1450)$, we take them as $q\bar{q}$ states. For axial-vector meson, we study $a_{1}(1260)( 1^{3}p^{1})$ and $b_{1}(1235)( 1^{1}p^{1})$. Based on the results of these form factors, we further present the branching ratios of these semileptonic decay processes. The numerical results for $ D\rightarrow a_{0}(980), b_{1}(1235)l\bar{ν_{l}} $ are in good agreement with experiments and that for $ D\rightarrow a_{0}(1450)l\bar{ν_{l}}$ process are expected to be tested experimentally in the future.

hep-ph↗

arXiv2020

$Z_{cs}(3985)^-$: a strange hidden-charm tetraquark resonance or not?

Inspired by the newly $Z_{cs}(3985)^-$ reported by the BESIII Collaboration in the $K^+$ recoil-mass spectrum of the of $e^+e^-\to (D^{*0}D_s^-/D^0D_s^{*-})K^+$ processes, we perform a dynamical study on the $D^{(*)0}D_s^{*-}$ interactions by adopting a one-boson-exchange model and considering the coupled channel effect. After producing the phase shifts for all the discussed channels, our results exclude the newly $Z_{cs}(3985)^-$ as a $D^{*0}D_s^{-}/D^{0}D_s^{*-}/D^{*0}D_s^{*-}$ resonance with $I(J^P)=1/2(1^+, 0^-, 1^-, 2^-)$.

hep-ph↗

arXiv2020

Systematic Generalization on gSCAN with Language Conditioned Embedding

Systematic Generalization refers to a learning algorithm's ability to extrapolate learned behavior to unseen situations that are distinct but semantically similar to its training data. As shown in recent work, state-of-the-art deep learning models fail dramatically even on tasks for which they are designed when the test set is systematically different from the training data. We hypothesize that explicitly modeling the relations between objects in their contexts while learning their representations will help achieve systematic generalization. Therefore, we propose a novel method that learns objects' contextualized embeddings with dynamic message passing conditioned on the input natural language and end-to-end trainable with other downstream deep learning modules. To our knowledge, this model is the first one that significantly outperforms the provided baseline and reaches state-of-the-art performance on grounded-SCAN (gSCAN), a grounded natural language navigation dataset designed to require systematic generalization in its test splits.

cs.AI↗

arXiv2020

Model-Free Voltage Regulation of Unbalanced Distribution Network Based on Surrogate Model and Deep Reinforcement Learning

Accurate knowledge of the distribution system topology and parameters is required to achieve good voltage controls, but this is difficult to obtain in practice. This paper develops a model-free approach based on the surrogate model and deep reinforcement learning (DRL). We have also extended it to deal with unbalanced three-phase scenarios. The key idea is to learn a surrogate model to capture the relationship between the power injections and voltage fluctuation of each node from historical data instead of using the original inaccurate model affected by errors and uncertainties. This allows us to integrate the DRL with the learned surrogate model. In particular, DRL is applied to learn the optimal control strategy from the experiences obtained by continuous interactions with the surrogate model. The integrated framework contains training three networks, i.e., surrogate model, actor, and critic networks, which fully leverage the strong nonlinear fitting ability of deep learning and DRL for online decision making. Several single-phase approaches have also been extended to deal with three-phase unbalance scenarios and the simulation results on the IEEE 123-bus system show that our proposed method can achieve similar performance as those that use accurate physical models.

eess.SY↗

arXiv2020

Heterogeneous Graph Attention Networks for Early Detection of Rumors on Twitter

With the rapid development of mobile Internet technology and the widespread use of mobile devices, it becomes much easier for people to express their opinions on social media. The openness and convenience of social media platforms provide a free expression for people but also cause new social problems. The widespread of false rumors on social media can bring about the panic of the public and damage personal reputation, which makes rumor automatic detection technology become particularly necessary. The majority of existing methods for rumor detection focus on mining effective features from text contents, user profiles, and patterns of propagation. Nevertheless, these methods do not take full advantage of global semantic relations of the text contents, which characterize the semantic commonality of rumors as a key factor for detecting rumors. In this paper, we construct a tweet-word-user heterogeneous graph based on the text contents and the source tweet propagations of rumors. A meta-path based heterogeneous graph attention network framework is proposed to capture the global semantic relations of text contents, together with the global structure information of source tweet propagations for rumor detection. Experiments on real-world Twitter data demonstrate the superiority of the proposed approach, which also has a comparable ability to detect rumors at a very early stage.

cs.SI↗

arXiv2020

Buried spatially-regular array of spectrally ultra-uniform single quantum dots for on-chip scalable quantum optical circuits

A long standing obstacle to realizing highly sought on-chip monolithic solid state quantum optical circuits has been the lack of a starting platform comprising buried (protected) scalable spatially ordered and spectrally uniform arrays of on-demand single photon sources (SPSs). In this paper we report the first realization of such SPS arrays based upon a class of single quantum dots (SQDs) with single photon emission purity > 99.5% and uniformity < 2nm. Such SQD synthesis approach offers rich flexibility in material combinations and thus can cover the emission wavelength regime from long- to mid- to near-infrared to the visible and ultraviolet. The buried array of SQDs naturally lend themselves to the fabrication of quantum optical circuits employing either the well-developed photonic 2D crystal platform or the use of Mie-like collective resonance of all-dielectric building block based metastructures designed for directed emission and manipulation of the emitted photons in the horizontal planar architecture inherent to on-chip optical circuits. Finite element method-based simulations of the Mie-resonance based manipulation of the emitted light are presented showing achievement of simultaneous multifunctional manipulation of photons with large spectral bandwidth of ~ 20nm that eases spectral and mode matching. Our combined experimental and simulation findings presented here open the pathway for fabrication and study of on-chip quantum optical circuits.

physics.app-ph↗

arXiv2020

Distributed Voltage Regulation of Active Distribution System Based on Enhanced Multi-agent Deep Reinforcement Learning

This paper proposes a data-driven distributed voltage control approach based on the spectrum clustering and the enhanced multi-agent deep reinforcement learning (MADRL) algorithm. Via the unsupervised clustering, the whole distribution system can be decomposed into several sub-networks according to the voltage and reactive power sensitivity. Then, the distributed control problem of each sub-network is modeled as Markov games and solved by the enhanced MADRL algorithm, where each sub-network is modeled as an adaptive agent. Deep neural networks are used in each agent to approximate the policy function and the action value function. All agents are centrally trained to learn the optimal coordinated voltage regulation strategy while executed in a distributed manner to make decisions based on only local information. The proposed method can significantly reduce the requirements of communications and knowledge of system parameters. It also effectively deals with uncertainties and can provide online coordinated control based on the latest local information. Comparison results with other existing model-based and data-driven methods on IEEE 33-bus and 123-bus systems demonstrate the effectiveness and benefits of the proposed approach.

eess.SY↗

arXiv2020

Nonlinear Virtual Inertia Control of WTGs for Enhancing Primary Frequency Response and Suppressing Drive-Train Torsional Oscillations

Virtual inertia controllers (VICs) for wind turbine generators (WTGs) have been recently developed to compensate for the reduction of inertia in power systems. However, VICs can induce low-frequency torsional oscillations of the drive train of WTGs. This paper addresses this issue and develops a new nonlinear VIC based on objective holographic feedbacks theory. This approach allows transforming the objectives that require improvement into a completely controllable system of Brunovsky's type. Simulation results under various scenarios demonstrate that the proposed method outperforms existing VICs in terms of suppression of WTG low-frequency drive-train torsional oscillations, enhancement of system frequency nadir as well as fast and smooth recovery of WTG rotor speed to the original MPP before the disturbance. The proposed method is also able to coordinate multiple WTGs.

eess.SY↗

arXiv2019

AliMe KBQA: Question Answering over Structured Knowledge for E-commerce Customer Service

With the rise of knowledge graph (KG), question answering over knowledge base (KBQA) has attracted increasing attention in recent years. Despite much research has been conducted on this topic, it is still challenging to apply KBQA technology in industry because business knowledge and real-world questions can be rather complicated. In this paper, we present AliMe-KBQA, a bold attempt to apply KBQA in the E-commerce customer service field. To handle real knowledge and questions, we extend the classic "subject-predicate-object (SPO)" structure with property hierarchy, key-value structure and compound value type (CVT), and enhance traditional KBQA with constraints recognition and reasoning ability. We launch AliMe-KBQA in the Marketing Promotion scenario for merchants during the "Double 11" period in 2018 and other such promotional events afterwards. Online results suggest that AliMe-KBQA is not only able to gain better resolution and improve customer satisfaction, but also becomes the preferred knowledge management method by business knowledge staffs since it offers a more convenient and efficient management experience.

cs.AI↗

arXiv2019

Study of the radiative decay $J/ψ\rightarrowη_{c}+γ$ in light cone sum rules

At present, there are many experimental and theoretical results for $J/ψ\rightarrowη_{c}+γ$ process, while the results are inconsistent based on different methods and considerations. In this paper, the light cone sum rules method is used in studying the radiative decay $J/ψ\rightarrowη_{c}+γ$. We give the transition form factor of this process based on the leading twist distribution amplitude of $η_{c}$ meson, with this form factor further obtain the decay width. Our result is consistent with those of other sum rules. A comparison of our result with others' about the decay width is also presented.

hep-ph↗

arXiv2019

Single full gap with mixed type-I and type-II superconductivity on surface of the type-II Dirac semimetal PdTe2 by point-contact spectroscopy

We report our point-contact spectroscopy (PCS) study on the superconducting state of the type-II Dirac semimetal PdTe$_2$ with a superconducting transition temperature $T\rm_c \sim$ 1.65 K. Both mechanical- and soft- PCS differential conductance curves at 0.3 K show a consistent double-peak structure and they can be perfectly fitted by a single s-wave gap based on the Blonder-Tinkham-Klapwijk model. The gap follows a typical Bardeen-Cooper-Schrieffer temperature behavior, yielding $Δ_0 \sim$ 0.29 meV and 2$Δ_0$/$k\rm_{B}$$T\rm_{c}$ = 4.15 in the strong coupling regime. A sudden suppression of the superconducting gap in magnetic field around $H{\rm_{c1}}$ $\sim$ 130 Oe is observed for most point-contacts on PdTe$_2$, characteristic of a first-order transition for type-I superconductor in field. However, for other contacts, a smooth evolution of the PCS conductance persists up to $H{\rm_{c2}}$ $\sim$ 600 Oe, signaling a local type-II superconductivity. The observed admixture of type-I and type-II superconductivity can possibly arise from an inhomogeneous electron mean free path on the surface of PdTe$_2$ due to its topological surface states.

cond-mat.supr-con↗

arXiv2019

Charged charmoniumlike structures in the $e^+ e^- \to ψ(3686) π^+ π^-$ process based on the ISPE mechanism

In 2017, the BESIII Collaboration announced the observation of a charged charmonium-like structure in the $ψ(3686)π^\pm$ invariant mass spectrum of the $e^+ e^- \to ψ(3686) π^+ π^-$ process at different energy points, which enables us to perform a precise study of this process based on the initial single pion emission (ISPE) mechanism. In this work, we perform a combined fit to the experimental data of the cross section of $e^+ e^- \to ψ(3686) π^+ π^-$, and the corresponding $ψ(3686)π^\pm$ and dipion invariant mass spectra. Our result shows that the observed charged charmonium-like structure in $e^+ e^- \to ψ(3686) π^+ π^-$ can be well reproduced based on the ISPE mechanism, and that the corresponding dipion invariant mass spectrum and cross section can be depicted with the same parameters. In fact, it provides strong evidence that the ISPE mechanism can be an underlying mechanism resulting in such novel a phenomenon.

hep-ph↗

arXiv2019

The Excited Charmonium Production in $e^{+}e^{-}$ Annihilation

We calculate the form factor and cross section of the excited charmonium production process $e^{+}+e^{-}\rightarrow ψ\left ( 2S \right )+η_{c}$ by light-cone sum rules. In our method, the form factor depends on the distribution amplitude of $η_{c}$ meson. Experimentally, the energy scale of $e^{+}+e^{-}\rightarrow ψ\left ( 2S \right )+η_{c}$ process is much larger than the initial energy scale of $η_{c}$ meson in our BHL model. Therefore, we further consider the evolution of the distribution amplitude with the energy scale, and select the distribution amplitude as our input parameter when the final effective energy scale is $μ=5.00\ GeV$. This treatment means that we have chosen the relativistic distribution amplitude. The results show that the relativistic effect contributes greatly to the form factor and cross section. Our results are consistent with Belle experimental data.

hep-ph↗

arXiv2018

Analysis of Bag-of-n-grams Representation's Properties Based on Textual Reconstruction

Despite its simplicity, bag-of-n-grams sen- tence representation has been found to excel in some NLP tasks. However, it has not re- ceived much attention in recent years and fur- ther analysis on its properties is necessary. We propose a framework to investigate the amount and type of information captured in a general- purposed bag-of-n-grams sentence represen- tation. We first use sentence reconstruction as a tool to obtain bag-of-n-grams representa- tion that contains general information of the sentence. We then run prediction tasks (sen- tence length, word content, phrase content and word order) using the obtained representation to look into the specific type of information captured in the representation. Our analysis demonstrates that bag-of-n-grams representa- tion does contain sentence structure level in- formation. However, incorporating n-grams with higher order n empirically helps little with encoding more information in general, except for phrase content information.

cs.CL↗

arXiv2018

Proposal of searching for the $Υ(6S)$ hadronic decays into $Υ(nS)$ plus $η^{(\prime)}$

In this work, we propose a possible experimental research topic on the $Υ(6S)\to Υ(nS)η^{(\prime)}$ ($n=1,2,3$) transitions. Considering the hadronic loop effect from the intermediate $S$-wave $B_{(s)}$ and $B_{(s)}^*$ mesons, we estimate the partial decay widths and the corresponding branching ratios of the $Υ(6S)\to Υ(nS)η^{(\prime)}$ hadronic decays, which become considerably large. With the running of the Belle II experiment, it becomes possible to explore these $Υ(6S)\to Υ(nS)η^{(\prime)}$ transitions.

hep-ph↗

arXiv2018

Potential observation of the $Υ(6S) \to Υ(1^3D_J) η$ transitions at Belle II

We perform the investigation of two-body hidden-bottom transitions of the $Υ(6S)$, which include $Υ(6S) \to Υ(1^3D_J) η~~(J=1,2,3)$ decays. For estimating the branching ratios of these processes, we consider contributions from the triangle hadronic loops composed of S-wave $B_{(s)}$ and $B_{(s)}^*$ mesons, which are a bridge to connect the $Υ(6S)$ and final states. Our results show that both of the branching ratios of these decays can reach $10^{-3}$. Due to such considerable potential to observe these two-body hidden-bottom transitions of the $Υ(6S)$, we suggest the forthcoming Belle II experiment to explore them.

hep-ph↗

arXiv2017

Exploring the $Υ(6S)\to χ_{bJ}ϕ$ and $Υ(6S)\to χ_{bJ}ω$ hidden-bottom hadronic transitions

In this work, we investigate the hadronic loop contributions to the $Υ(6S) \to χ_{bJ} ϕ~(J=0,1,2)$ along with $Υ(6S) \to χ_{bJ} ω~(J=0,1,2)$ transitions. We predict that the branching ratios of $Υ(6S) \to χ_{b0} ϕ$, $Υ(6S) \to χ_{b1} ϕ$ and $Υ(6S) \to χ_{b2} ϕ$ are $(0.68 \sim 4.62) \times 10^{-6}$, $(0.50 \sim 3.43) \times 10^{-6}$ and $(2.22 \sim 15.18) \times 10^{-6}$, respectively and those of $Υ(6S) \to χ_{b0} ω$, $Υ(6S) \to χ_{b1} ω$ and $Υ(6S) \to χ_{b2} ω$ are $(0.15 \sim 2.81) \times 10^{-3}$, $(0.63 \sim 11.68) \times 10^{-3}$ and $(1.08 \sim 20.02) \times 10^{-3}$, respectively. Especially, some typical ratios, which reflect the relative magnitudes of the predicted branching ratios, are given, i.e., for $Υ(6S)\to χ_{bJ}ϕ$ transitions, $\mathcal{R}^ϕ_{10}={\mathcal{B}[Υ(6S) \to χ_{b1} ϕ]}/{\mathcal{B}[Υ(6S) \to χ_{b0} ϕ]} \approx 0.74$, $\mathcal{R}^ϕ_{20}= {\mathcal{B}[Υ(6S) \to χ_{b2} ϕ]}/{\mathcal{B}[Υ(6S) \to χ_{b0} ϕ]} \approx 3.28$, and $\mathcal{R}^ϕ_{21} = {\mathcal{B}[Υ(6S) \to χ_{b2} ϕ]}/{\mathcal{B}[Υ(6S) \to χ_{b1} ϕ]} \approx 4.43$, and for $Υ(6S)\to χ_{bJ}ω$ transitions, $\mathcal{R}^ω_{10}={\mathcal{B}[Υ(6S) \to χ_{b1} ω]}/{\mathcal{B}[Υ(6S) \to χ_{b0} ω]} \approx 4.11$, $\mathcal{R}^ω_{20}= {\mathcal{B}[Υ(6S) \to χ_{b2} ω]}/{\mathcal{B}[Υ(6S) \to χ_{b0} ω]} \approx 7.06$, and $\mathcal{R}^ω_{21} = {\mathcal{B}[Υ(6S) \to χ_{b2} ω]}/{\mathcal{B}[Υ(6S) \to χ_{b1} ω]} \approx 1.72$. With the running of BelleII in the near future, experimental measurement of these two kinds of transitions will be a potential research issue.

hep-ph↗

arXiv2014

Numerical analysis of the production of $D^{(*)}(3000)$, $D_{sJ}(3040)$ and their partners through the semileptonic decays of $B_{(s)}$ mesons in terms of the light-front quark model

Inspired by the newly observed $D^{(*)}(3000)$, and $D_{sJ}(3040)$ states, in this work we study the production of $D^{(*)}(3000)$, $D_{sJ}(3040)$ and their partners through the semileptonic decays of $B_{(s)}$ mesons, where the light-front Quark model is applied to the whole calculation. Our numerical results indicate that the $B_{(s)}$ semileptonic decays into the $2P$ states of the charmed or charmed-strange meson family have considerable branching ratios, which shows that these semileptonic decays can be accessible at future experiments, especially LHCb and the forthcoming Belle II.

hep-ph↗