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Dynamical relaxation behavior of extended XY chain with gapless phase following a quantum quench

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arXiv 2023年

作者： Cao, Kaiyuan Hu, Yayun Tong, Peiqing Yang, Guangwen 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

We investigate the dynamical relaxation behavior of the two-point correlation in extended XY models with a gapless phase after quenches from various initial states. Specifically, we study the XY chain with gapless phase induced by the additional interactions: Dzyaloshinskii-Moriya interaction and XZY-YZX type of three-site interaction. When quenching from the gapped phase, we observe that the additional interactions have no effect on the relaxation behavior. The relaxation behavior is δCmn(t) ∼ t−3/2 and ∼ t−1/2 for the quench to the commensurate phase and the incommensurate phase, respectively. However, when quenching from the gapless phase, we demonstrate that the scaling behavior of δCmn(t) is changed to ∼ t−1 for the quench to the commensurate phase, and the decay of δCmn(t) follows ∼ t−1 or ∼ t−1/2 for the quench to the incommensurate phase depending on the parameters of pre-quench Hamiltonian. We also establish the dynamical phase diagrams based on the dynamical relaxation behavior of δCmn(t) in the extended XY models. Copyright © 2023, The Authors. All rights reserved.

关键词： Quenching

The sQ¯ q¯ q (q = u, d;Q = c, b) tetraquarks in the chiral quark model

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arXiv 2021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 sQq¯q¯ (q = u, d, Q = c, b) tetraquark states with JP = 0+, 1+ and 2+, and in the isoscalar and isovector sectors, are systematically investigated in the framework of real- and complex-scaling range of a chiral quark model, whose parameters have been fixed in advance describing hadron, hadron-hadron and multiquark phenomenology, and thus all results presented here are pure predictions. Each tetraquark configuration, compatible with the quantum numbers studied, is taken into account;this includes meson-meson, diquark-antidiquark and K-type arrangements of quarks with all possible color wave functions in four-body sector. Among the different numerical techniques to solve the Schrödinger-like 4-body bound state equation, we use a variational method in which the trial wave function is expanded in complex-range Gaussian basis functions, because its simplicity and flexibility. Several compact bound states and narrow resonances are found in both charm-strange csq¯q¯ and bottom-strange bsq¯q¯ tetraquark sectors, most of them as a product of the strong coupling between the different channels. The so-called X0,1(2900) signals, recently found by the LHCb collaboration, are unstable in our formalism with several candidates in the single-channel computations. Copyright © 2021, The Authors. All rights reserved.

关键词： Hadrons

Doubly Charmed Pentaquarks

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arXiv 2020年

The LHCb Collaboration, using its full data set from runs 1 and 2, announced in 2019 a surprising update of the hidden-charm pentaquark states Pc(4380)+ and Pc(4450)+, observed in 2015. A new state, Pc(4312)+, was clearly seen at lower energies;furthermore, the original Pc(4450) resonance was resolved into two individual states, named the Pc(4440)+ and the Pc(4457)+. Motivated by the fact that these new hidden-charm pentaquark states were successfully predicted by our chiral quark model, we extend herein such study to the doubly charmed sector. The analyzed total spin and parity quantum numbers are JP = 21 − , 32− and 25 −, in the I = 12 and 23 isospin channels. We find several possible narrow baryon-meson resonances (theoretical masses in parenthesis): IJP = 1212− ΣcD(4356), 12 23 − Σ∗cD(4449), 3212− ΣcD(4431), 3212− ΣcD(4446), 3232− ΣcD∗(4514) and 23 52− Ξ∗ccρ(4461) whose widths are 4.8, 8.0, 2.6, 2.2, 4.0 and 3.0 MeV, respectively. Moreover, one shallow bound-state is found, too, with quantum numbers IJP = 21 32− Ξ∗ccπ(3757). These doubly charmed pentaquark states are expected to be identified in future experiments. Copyright © 2020, 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

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

Directed momentum current induced by the PT-symmetric driving

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Physical Review E 2019年第4期99卷 042201-042201页

作者： Wen-Lei Zhao Jiaozi Wang Xiaohui Wang Peiqing Tong School of Science Jiangxi University of Science and Technology Ganzhou 341000 China Department of Modern Physics University of Science and Technology of China Hefei 230026 China School of Information Engineering Jiangxi University of Science and Technology Ganzhou 341000 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

We investigate the directed momentum current in the quantum kicked rotor model with PT-symmetric deriving potential. For the quantum nonresonance case, the values of quasienergy become complex when the strength of the 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 quasienergy 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.

关键词： Coherent control Cold atoms & matter waves Light-matter interaction Wave chaos

NLO twist-3 contributions to B→π form factors in kT factorization

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Physical Review D 2014年第9期89卷 094004-094004页

作者： Shan Cheng Ying-Ying Fan Xin Yu Cai-Dian Lü Zhen-Jun Xiao Department of Physics and Institute of Theoretical Physics Nanjing Normal University Nanjing Jiangsu 210023 People’s Republic of China Institute of High Energy Physics and Theoretical Physics Center for Science Facilities Chinese Academy of Sciences Beijing 100049 People’s Republic of China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210023 People’s Republic of China

In this paper, we calculate the next-to-leading-order (NLO) twist-3 contribution to the form factors of B→π transitions by employing the kT factorization theorem. All the infrared divergences regulated by the logarithms ln(kiT2) cancel between those from the quark diagrams and from the effective diagrams for the initial B meson wave function and the final pion meson wave function. An infrared finite NLO hard kernel is, therefore, obtained, which confirms the application of the kT factorization theorem to the B meson semileptonic decays at the twist-3 level. From our analytical and numerical evaluations, we find that the NLO twist-3 contributions to the form factors f+,0(q2) of the B→π transition are similar in size but have an opposite sign with the NLO twist-2 contribution, which leads to a large cancellation between these two NLO parts. For the case of f+(0), for example, the 24% NLO twist-2 enhancement to the full LO prediction is largely canceled by the negative (about −17%) NLO twist-3 contribution, leaving a small and stable 7% enhancement to the full LO prediction in the whole range of 0≤q2≤12 GeV2. At the full NLO level, the perturbative QCD prediction is FB→π(0)=0.269−0.050+0.054. We also study the possible effects on the perturbative QCD predictions when different sets of the B meson and pion distribution amplitudes are used in the numerical evaluation.

关键词：

B(s) → ηc(P, V) decays and effects of the next-to-leading order contributions in the perturbative QCD approach

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arXiv 2019年

作者： Xiao, Zhen-Jun Yan, Da-Cheng Liu, Xin Department of Physics Institute of Theoretical Physics Nanjing Normal University Nanjing Jiangsu210023 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing Jiangsu210023 China School of Mathematics and Physics Changzhou University Changzhou213164 China Department of Physics Jiangsu Normal University Xuzhou221116 China

By employing the perturbative QCD (PQCD) factorization approach, we studied the sixteen B/Bs → ηc(π, K, η(′), ρ, K∗, ω, φ) decays with the inclusion of the currently known next-to-leading order (NLO) contributions. We found the following main points: (a) for the five measured B → ηc(K, K∗) and Bs → ηcφ decays, the NLO contributions can provide (80 − 180)% enhancements to the leading order (LO) PQCD predictions of their branching ratios, which play an important role to help us to interpret the data;(b) for the seven ratios R1,···,7 of the branching ratios defined among the properly selected pair of the considered decay modes, the PQCD predictions for the values of R3,4,5 agree well with those currently available BaBar and Belle measurements;(c) for B0 → ηcKS0 decay, the PQCD predictions for both the direct and mixing induced CP asymmetries do agree very well with the measured values within errors;and (d) the PQCD predictions for ratios R1,2 and R6,7 also agree with the general expectations and will be tested by the future experiments. Copyright © 2019, The Authors. All rights reserved.

关键词： Forecasting

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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