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Search for doubly-heavy dibaryons in the quark-delocalization color-screening model

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arXiv 2021年

作者： Xia, Zhuocheng Fan, Saijun Zhu, Xinmei Huang, Hongxia Ping, Jialun Department of Physics Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 China Department of Physics Yangzhou University Yangzhou225009 China

We perform a systemical investigation of the low-lying doubly-heavy dibaryon systems with strange S = 0, isospin I = 0, 1, 2 and the angular momentum J = 0, 1, 2, 3 in the quark de- localization color screening model. We find the effect of channel-coupling cannot be neglected in the study of the multi-quark systems. Due to the heavy flavor symmetry, the results of the doubly- charm and doubly-bottom dibaryon systems are similar with each other. Both of them have three bound states, the quantum numbers of which are IJ = 00, IJ = 02 and IJ = 13, respectively. The energies are 4554 MeV, 4741 MeV, and 4969 MeV respectively for the doubly-charm systems and 11219 MeV, 11416 MeV, and 11633 MeV respectively for the doubly-bottom dibaryon systems. Besides, six resonance states are obtained, which are IJ = 00 NΞccand NΞbbwith resonance mass of 4716 MeV and 11411 MeV respectively, IJ = 11 NΞ∗ccand NΞ∗bbwith resonance mass of 4757 MeV and 11432 MeV respectively, and IJ = 12 ΣcΣ∗cand ΣbΣ∗bwith resonance mass of 4949 MeV and 11626 MeV respectively. All these heavy dibaryons are worth searching for on experiments, although it will be a challenging work. © 2021, CC BY.

关键词： Resonance

A novel class of energy-preserving Runge-Kutta methods for the Korteweg-de Vries equation

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arXiv 2021年

作者： Chen, Yue Gong, Yuezheng Hong, Qi Wang, Chunwu Department of Mathematics Nanjing University of Aeronautics and Astronautics Nanjing211106 China MIIT Nanjing211106 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing210023 China

In this paper, we present a quadratic auxiliary variable approach to develop a new class of energy-preserving Runge-Kutta methods for the Korteweg-de Vries equation. The quadratic auxiliary variable approach is first proposed to reformulate the original model into an equivalent system, which transforms the energy conservation law of the Korteweg-de Vries equation into two quadratic invariants of the reformulated system. Then the symplectic Runge-Kutta methods are directly employed for the reformulated model to arrive at a new kind of time semi-discrete schemes for the original problem. Under the consistent initial condition, the proposed methods are rigorously proved to maintain the original energy conservation law of the Korteweg-de Vries equation. In addition, the Fourier pseudo-spectral method is used for spatial discretization, resulting in fully discrete energy-preserving schemes. To implement the proposed methods effectively, we present a very efficient iterative technique, which not only greatly saves the calculation cost, but also achieves the purpose of practically preserving structure. Ample numerical results are addressed to confirm the expected order of accuracy, conservative property and efficiency of the proposed algorithms. Copyright © 2021, The Authors. All rights reserved.

关键词： Runge Kutta methods

Non-Rigid Metal–Oxygen Bonding Empowered Nitrate Reduction on Ruthenium Catalysts

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SSRN

SSRN 2024年

作者： Wang, Suwen Zhuang, Zechao Xu, Jiawei Fu, Cheng Qiu, Zhen Feng, Huajun Xiang, Hai Chen, Zuliang Li, Hui Zhang, Lei Li, Yongfu Cai, Yanjiang Ma, Tianyi Yu, Bing State Key Laboratory of Subtropical Silviculture Zhejiang A&F University Hangzhou311300 China Zhejiang A&F University Hangzhou311300 China Department of Chemistry Tsinghua University Beijing100084 China Jiangsu Key Laboratory of Numerical Simulation of Large Scale Complex Systems School of Chemistry and Materials Science Nanjing Normal University Nanjing210023 China Fujian Key Laboratory of Pollution Control and Resource Reuse School of Environmental and Resource Sciences Fujian Normal University Fujian Province Fuzhou350007 China School of Science RMIT University MelbourneVIC3000 Australia Centre for Translational Atomaterials

Electrocatalytic nitrate reduction (NitRR) offers exciting potential for mass production of ammonia (NH3) from renewables. However, the rigidity of metal−ligand bonds in most electrocatalysts renders them unable to survive the structural transformations required for NitRR. Herein, we establish a type of non-rigid metal−oxygen bonds by employing graphene oxide (GO) sheets as a 'micron-scale' ligand for transition metals (TM). Because of being confined to the interfaces between GO and TM, the oxygenated groups in GO can associate with and dissociate from the TM in response to reaction dynamics. As a proof-of-concept demonstration, an electrocatalyst was developed by dispersing nanoscale ruthenium (Ru) on graphene oxide (GO) and utilizing two-dimensional MXene to compensate for the low electrical conductivity of GO. This electrocatalyst exhibits a maximum NH3 yield of over 5 mg cm−2 h−1, with almost 100% current-to-NH3 efficiency, far outperforming the performance of most reported Ru-based materials. What's even more remarkable is the achievement of a record-breaking performance: a 200-hour stable electrolysis with a NH3 yield of 40.2 mg cm−2 h−1, using a membrane electrode reactor. Our experimental and theoretical investigations further reveal the non-rigidity of the Ru–O bonds and how they self-regulate to adapt to diverse intermediates involved in NitRR. This work provides an approach to fabricate a high-performance electrocatalyst featuring reversible and non-rigid metal−oxygen bonds, opening new possibilities for practical nitrate electrolysis. © 2024, The Authors. All rights reserved.

关键词： Electrocatalysis

Bottomoniumlike tetraquarks in a chiral quark model

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Physical Review D 2022年第1期106卷 014021-014021页

作者： Gang Yang Jialun Ping Jorge Segovia Department of Physics Zhejiang Normal University Jinhua 321004 China Department of Physics and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210023 People’s Republic of China Departamento de Sistemas Físicos Químicos y Naturales Universidad Pablo de Olavide E-41013 Sevilla Spain

The low-lying bottomoniumlike tetraquarks bb¯qq¯ (q=u, d, s) with spin-parity JP=0+, 1+, and 2+, and isospin I=0, 1, or 12, are systematically investigated within the theoretical framework of real- and complex-scaling range of a chiral quark model, which has already been successfully applied in analysis of several multiquark systems. A complete four-body S-wave function, which includes meson-meson, diquark-antidiquark and K-type arrangements of quarks, along with all possible color configurations are considered. In the bb¯qq¯ (q=u, d) tetraquark system, we found resonance states of B(*)B¯(*), ϒω, ϒρ, and ηbρ nature with all possible I(JP) quantum numbers. Their masses are generally located in the energy range 11.0–11.3 GeV and their widths are less than 10 MeV. In addition, extremely narrow resonances, with two-meson strong decay widths less than 1.5 MeV, are obtained in both bb¯us¯ and bb¯ss¯ tetraquark systems. Particularly, four radial excitations of ϒK* and ηbK* are found at ∼11.1 GeV in JP=0+, 1+, and 2+ channels of bb¯us¯ system. One ϒ(1S)ϕ(2S) resonance state is obtained at 11.28 GeV in the JP=1+ sector.

关键词： Quantum chromodynamics Quark model Strong interaction

Dynamical quantum phase transition in quantum spin chains with gapless phases

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arXiv 2021年

作者： Cao, Kaiyuan Ming, Zhong Tong, Peiqing Department of Physics Institute of Theoretical Physics Nanjing Normal University Nanjing210023 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 China

The dynamical quantum phase transitions (DQPTs) in quantum spin chains with gapless phases after a sudden quench are studied. We mainly consider the general systems with asymmetrical quasiparticle excitation spectra and obtain the general expression of the Loschmidt echo as well as the general conditions for the occurrence of DQPTs. As two examples, we study the DQPTs in the XY chains with Dzyaloshinskii-Moriya interaction and XZY-YZX type of three-site interaction. It's found that the DQPTs may not occur in the quench across the quantum phase transitions regardless of whether the quench is from the gapless phase to gapped phase or from the gapped phase to gapless phase. This is different from the DQPTs in the case of quench from the gapped phase to gapped phase, in which the DQPTs will always appear. Besides, we also analyze the different reasons for the absence of DQPTs in the quench from the gapless phase and the gapped phase. © 2021, CC BY.

关键词： Phase transitions

Relaxation dynamics in the alternating XY chain following a quantum quench

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arXiv 2023年

作者： Cao, Kaiyuan Hu, Yayun Tong, Peiqing Yang, Guangwen Liu, Peng Zhejiang Lab Hangzhou311100 China Department of Physics Institute of Theoretical Physics Nanjing Normal University Nanjing210023 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 China Department of Computer Science and Technology Tsinghua University Haidian District Beijing100084 China College of Information Science and Electronic Engineering Zhejiang University Hangzhou310027 China

We investigate the relaxation dynamics of the fermion two-point correlation function Cmn(t) = 〈ψ(t)|c†mcn|ψ(t)〉 in the XY chain with alternating nearest-neighbor hopping interaction after a quench. We find that the deviation δCmn(t) = Cmn(t) − Cmn(∞) decays with time following the power law behavior t−µ, where the exponent µ depends on whether the quench is to the commensurate phase (µ = 1) or incommensurate phase (µ = 1/2). This decay of δCmn(t) arises from the transient behavior of the double-excited quasiparticle occupations and the transitions between different excitation spectra. Furthermore, we find that the steady value Cmn(∞) only involves the average fermion occupation numbers (i.e. the average excited single particle) over the time-evolved state, which are different from the ground state expectation values. We also observe nonanalytic singularities in the steady value Cmn(∞) for the quench to the critical points of the quantum phase transitions (QPTs), suggesting its potential use as a signature of QPTs. Copyright © 2023, The Authors. All rights reserved.

关键词： Ground state

A hybrid phase field method for fluid-structure interactions in viscous fluids

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arXiv 2021年

作者： Hong, Qi Wang, Qi College of Science Nanjing University of Aeronautics and Astronautics Nanjing210016 China MIIT Nanjing211106 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex System Department of Mathematics University of South Carolina ColumbiaSC29208 United States

We present a novel computational modeling framework to numerically investigate fluid-structure interaction in viscous fluids using the phase field embedding method. Each rigid body or elastic structure immersed in the incompressible viscous fluid matrix, grossly referred to as the particle in this paper, is identified by a volume preserving phase field. The motion of the particle is driven by the fluid velocity in the matrix for passive particles or combined with its self-propelling velocity for active particles. The excluded volume effect between a pair of particles or between a particle and the boundary is modeled by a repulsive potential force. The drag exerted to the fluid by a particle is assumed proportional to its velocity. When the particle is rigid, its state is described by a zero velocity gradient tensor within the nonzero phase field that defines its profile and a constraining stress exists therein. While the particle is elastic, a linear constitutive equation for the elastic stress is provided within the particle domain. A hybrid, thermodynamically consistent hydrodynamic model valid in the entire computational domain is then derived for the fluid-particle ensemble using the generalized Onsager principle accounting for both rigid and elastic particles. Structure-preserving numerical algorithms are subsequently developed for the thermodynamically consistent model. numerical tests in 2D and 3D space are carried out to verify the rate of convergence and numerical examples are given to demonstrate the usefulness of the computational framework for simulating fluid-structure interactions for passive as well as self-propelling active particles in a viscous fluid matrix. Copyright © 2021, The Authors. All rights reserved.

关键词： Hydrodynamics

Bottomonium-like tetraquarks in a chiral quark model

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arXiv 2022年

作者： Yang, Gang Ping, Jialun Segovia, Jorge Department of Physics Zhejiang Normal University Jinhua321004 China Department of Physics Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 China Departamento de Sistemas Físicos Químicos y Naturales Universidad Pablo de Olavide SevillaE-41013 Spain

The low-lying bottomonium-like tetraquarks b(Equation presented)q(Equation presented) (q = u, d, s) with spin-parity JP = 0+, 1+ and 2+, and isospin I = 0, 1 or 1/2, are systematically investigated within the theoretical framework of real- and complex-scaling range of a chiral quark model, which has already been successfully applied in analysis of several multiquark systems. A complete four-body S-wave function, which includes meson-meson, diquark-antidiquark and K-type arrangements of quarks, along with all possible color configurations are considered. In the b(Equation presented)q(Equation presented) (q = u, d) tetraquark system, we found resonance states of B(*)(Equation presented)(*), Υω, Υρ and ηbρ nature with all possible I(JP) quantum numbers. Their masses are generally located in the energy range 11.0 − 11.3 GeV and their widths are less than 10 MeV. In addition, extremely narrow resonances, with two-meson strong decay widths less than 1.5 MeV, are obtained in both b(Equation presented)u(Equation presented) and b(Equation presented)s(Equation presented) tetraquark systems. Particularly, four radial excitations of ΥK∗ and ηbK∗ are found at ∼ 11.1 GeV in JP = 0+, 1+ and 2+ channels of b(Equation presented)u(Equation presented) system. One Υ(1S)φ(2S) resonance state is obtained at 11.28 GeV in the JP = 1+ sector. Copyright © 2022, The Authors. All rights reserved.

关键词： Hadrons

Fully-charm and -bottom pentaquarks in a Lattice-QCD inspired quark model

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arXiv 2022年

The fully-charm and -bottom pentaquarks, i.e. ccccc¯ and bbbb¯b, with spin-parity quantum numbers JP = 1/2− , 3/2− and 5/2−, are investigated within a Lattice-QCD inspired quark model, which has already successfully described the recently announced fully-charm tetraquark candidate X(6900), and has also predicted several other fully-heavy tetraquarks. A powerful computational technique, based on the Gaussian expansion method combined with a complex-scaling range approach, is employed to predict, and distinguish, bound, resonance and scattering states of the mentioned five-body system. Both baryon-meson and diquark-diquark-antiquark configurations, along with all of their possible color channels are comprehensively considered. Narrow resonances are obtained in each spin-parity channel for the fully-charm and -bottom systems. Moreover, most of them seems to be compact multiquarks whose wave-functions are dominated by either hidden-color baryon-meson or diquark-diquark-antiquark structure, or by the coupling between them. Copyright © 2022, The Authors. All rights reserved.

关键词： Hadrons