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Arbitrarily high-order structure-preserving schemes for the Gross-Pitaevskii equation with angular momentum rotation in three dimensions

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arXiv 2020年

作者： Cui, Jin Wang, Yushun Jiang, Chaolong Department of Basic Sciences Nanjing Vocational College of Information Technology Nanjing210023 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems School of Mathematical Sciences Nanjing Normal University Nanjing210023 China School of Statistics and Mathematics Yunnan University of Finance and Economics Kunming650221 China

In this paper, we design a novel class of arbitrarily high-order structure-preserving numerical schemes for the time-dependent Gross-Pitaevskii equation with angular momentum rotation in three dimensions. Based on the idea of the scalar auxiliary variable approach which is proposed in the recent papers [J. Comput. Phys., 416 (2018) 353-407 and SIAM Rev., 61(2019) 474-506] for developing energy stable schemes for gradient flow systems, we firstly reformulate the Gross-Pitaevskii equation into an equivalent system with a modified energy conservation law. The reformulated system is then discretized by the Gauss collocation method in time and the standard Fourier pseudo-spectral method in space, respectively. We show that the proposed schemes can preserve the discrete mass and modified energy exactly. numerical results are addressed to verify the efficiency and high-order accuracy of the proposed schemes. Copyright © 2020, The Authors. All rights reserved.

关键词： Bose-Einstein condensation

Superexponential diffusion in nonlinear non-Hermitian systems

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Physical Review A 2020年第6期102卷 062213-062213页

作者： Wen-Lei Zhao Longwen Zhou Jie Liu Peiqing Tong Kaiqian Huang School of Science Jiangxi University of Science and Technology Ganzhou 341000 China Department of Physics College of Information Science and Engineering Ocean University of China Qingdao 266100 China Graduate School of China Academy of Engineering Physics Beijing 100193 China CAPT HEDPS and IFSA Collaborative Innovation Center of the Ministry of Education Peking University Beijing 100871 China Department of Physics and Institute of Theoretical Physics Nanjing Normal University Nanjing 210023 China Jiangsu Provincial Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing Jiangsu 210023 China Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials SPTE South China Normal University Guangzhou 510006 China

We investigate the quantum diffusion of a periodically kicked particle subjected to both nonlinearity-induced self-interactions and PT-symmetric potentials. We find that, due to the interplay between the nonlinearity and non-Hermiticity, the expectation value of the mean square of momentum scales with time in a superexponential form 〈p2(t)〉∝exp[βexp(αt)], which is faster than any known rates of quantum diffusion. In the PT-symmetry-breaking phase, the intensity of a state increases exponentially with time, leading to the exponential growth of the interaction strength. The feedback of the intensity-dependent nonlinearity further turns the interaction energy into the kinetic energy, resulting in a superexponential growth of the mean energy. These theoretical predictions are in good agreement with numerical simulations in a PT-symmetric nonlinear kicked particle. Our discovery establishes a mechanism of diffusion in interacting and dissipative quantum systems. Important implications and possible experimental observations are discussed.

关键词： Anderson localization Atomic, optical & lattice clocks Diffusion Nonlinear optics Quantum transport Spatiotemporal chaos Wave chaos

Chaotic diffusion of complex trajectory and its quantum signature

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arXiv 2019年

作者： Zhao, Wen-Lei Wang, Jiaozi Wang, Qian Tong, Peiqing School of Science Jiangxi University of Science and Technology Ganzhou341000 China Department of Modern Physics University of Science and Technology of China Hefei230026 China Department of Physics Zhejiang Normal University Jinhua321004 China Department of Physics and Institute of Theoretical Physics Nanjing Normal University Nanjing210023 China Jiangsu Provincial Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing Jiangsu210023 China

We investigate both the quantum and classical dynamics of a non-Hermitian system via a kicked rotor model with PT symmetry. In non-Hermitian case, the classical trajectory is assumed to be complex. We find the normal diffusion for the real part of momentum and the exponentially-fast diffusion for the imaginary part of momentum. Due to the exponentially-fast increase of some trajectories, there is a threshold time for the breakdown of classical diffusion. Our theoretical prediction of such a threshold time is in good agreement with numerical results. The quantum signature of the chaotic diffusion of the complex trajectories is reflected by the dynamics of the out-of-time-order correlators (OTOC) in the semiclassical regime. We find that the growth of the OTOC exhibits a sharp transition to infinitely large at a critical time which exponentially increases with the increase of the threshold time of the classical diffusion. For the quantum dynamics, both the mean momentum and mean square of momentum exhibits the staircase growth with time when the system parameter is in the neighborhood of the PT symmetry breaking. If the system parameter is very larger than the PT symmetry breaking point, the acceleration mode results in the directed spreading of the wavepackets as well as the ballistic diffusion in momentum space. Copyright © 2019, The Authors. All rights reserved.

关键词： Momentum

Hidden-charm pentaquarks with strangeness in a chiral quark model

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arXiv 2023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 LHCb collaboration has recently announced the discovery of two hidden-charm pentaquark states with also strange quark content, Pcs(4338) and Pcs(4459);its analysis points towards having both hadrons isospin equal to zero and spin-parity quantum numbers 21 − and 32−, respectively. We perform herein a systematical investigation of the qqscc¯ (q = u, d) system by means of a chiral quark model, along with a highly accurate computational method, the Gaussian expansion approach combined with the complex-scaling technique. Baryon-meson configurations in both singlet- and hidden-color channels are considered. The Pcs(4338) and Pcs(4459) signals can be well identified as molecular bound states with dominant components ΛJ/ψ (60%) and ΞcD (23%) for the lowest-energy case and ΞcD∗ (72%) for the highest-energy one. Besides, it seems that some narrow resonances can be also found in each allowed I(JP)-channel in the energy region of 4.6 − 5.5 GeV, except for the 1(21 −) where a shallow bound state with dominant Ξ∗cD∗ structure is obtained at 4673 MeV with binding energy EB = −3 MeV. These exotic states are expected to be confirmed in future high energy experiments. Copyright © 2023, The Authors. All rights reserved.

关键词： Hadrons

Bottomonium-like tetraquarks in a chiral quark model

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arXiv 2022年

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

The q¯qs¯Q (q = u, d;Q = c, b) tetraquark system in a chiral quark model

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arXiv 2023年

Inspired by the experimentally reported Tcs¯(2900) exotic states, the S-wave q¯qs¯Q (q = u, d;Q = c, b) tetraquarks, with spin-parity JP = 0+, 1+ and 2+, in both isoscalar and isovector sectors are systematically studied in a chiral quark model. The meson-meson, diquark-antidiquark and K-type arrangements of quarks, along with all possible color wave functions, are comprehensively considered. The four-body system is solved by means of a highly efficient computational approach, the Gaussian expansion method, along with a complex-scaling formulation of the problem to disentangle bound, resonance and scattering states. This theoretical framework has already been successfully applied in various tetra- and penta-quark systems. In the complete coupled-channel case, and within the complex-range formulation, several narrow resonances of q¯qs¯c and q¯qs¯b systems are obtained in each allowed I(JP)-channels. Particularly, the Tcs¯(2900) is well identified as a I(JP) = 1(0+) q¯qs¯c tetraquark state with a dominant molecular structure. Meanwhile, more resonances in q¯qs¯c and q¯qs¯b systems are also obtained within the energy regions 2.4 − 3.4 GeV and 5.7 − 6.7 GeV, respectively. The predicted exotic states, which are an indication of a richer color structure when going towards multiquark systems beyond mesons and baryons, are expected to be confirmed in future high-energy particle and nuclear experiments. Copyright © 2023, The Authors. All rights reserved.

关键词： Germanium alloys

Directed momentum current induced by the PT -symmetric driving

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arXiv 2019年

作者： Zhao, Wen-Lei Wang, Jiaozi Wang, Xiaohui Tong, Peiqing School of Science Jiangxi University of Science and Technology Ganzhou341000 China Department of Modern Physics University of Science and Technology of China Hefei230026 China School of Information Engineering Jiangxi University of Science and Technology Ganzhou341000 China Department of Physics Institute of Theoretical Physics Nanjing Normal University Nanjing210023 China Jiangsu Provincial Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing Jiangsu210023 China

We investigate the directed momentum current in the quantum kicked rotor model with PT symmetric deriving potential. For the quantum non-resonance case, the values of quasi-energy become to be complex when the strength of imaginary part of the kicking potential exceeds a threshold value, which demonstrates the appearance of the spontaneous PT symmetry breaking. In the vicinity of the transition point, the momentum current exhibits a staircase growth with time. Each platform of the momentum current corresponds to the mean momentum of some eigenstates of the Floquet operator whose imaginary parts of the quasi-energy are significantly large. Above the transition point, the momentum current increases linearly with time. Interestingly, its acceleration rate exhibits a kind of "quantized" increment with the kicking strength. We propose a modified classical acceleration mode of the kicked rotor model to explain such an intriguing phenomenon. Our theoretical prediction is in good agreement with numerical results. Copyright © 2019, The Authors. All rights reserved.

关键词： Momentum

The ■ (q=u, d;Q=c, b) tetraquark system in a chiral quark model

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Chinese Physics C 2024年第7期 88-109页

作者：杨刚平加伦 Jorge Segovia Department of Physics Zhejiang Normal University Department of Physics and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Departamento de Sistemas Físicos Químicos y NaturalesUniversidad Pablo de Olavide

The S-wave ■（q=u,d;Q=c,b） tetraquarks,with spin-parities JP=0+,1+,and 2+,in both isoscalar and isovector sectors,are systematically studied using a chiral quark *** meson-meson,diquark-antidiquark,and K-type arrangements of quarks and all possible color wave functions are comprehensively *** four-body system is solved using the Gaussian expansion method,a highly efficient computational ***,a complex-scaling formulation of the problem is established to disentangle bound,resonance,and scattering *** theoretical framework has already been successfully applied in various tetra-and penta-quark *** the complete coupled channel and within the complex-range formulation,several narrow resonances of ■ systems are obtained,in each allowed I（JP）-channel,within the energy regions of 2.4-3.4 GeV and 5.7-6.7 GeV,*** predicted exotic states,which indicate a richer color structure when going towards multiquark systems beyond mesons and baryons,are expected to be confirmed in future high-energy particle and nuclear experiments.

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