检索结果-内蒙古大学图书馆

Dynamical quantum phase transition in quantum spin chains with gapless phases

学校读者我要写书评

暂无评论

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

Further study of the NΩ dibaryon within constituent quark models

学校读者我要写书评

暂无评论

Physical Review C 2015年第6期92卷 065202-065202页

作者： Hongxia Huang Jialun Ping Fan Wang 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 Department of Physics Nanjing University Nanjing 210093 People's Republic of China

Inspired by the discovery of the dibaryon d* and the experimental search of NΩ dibaryon with the STAR data, we study the strange dibaryon NΩ further in the framework of the quark delocalization color screening model and the chiral quark model. We have shown NΩ is a narrow resonance in ΛΞ D-wave scattering before. However, the Λ−Ξ scattering data analysis is quite complicated. Here we calculate the low-energy NΩ scattering phase shifts, scattering length, effective range, and binding energy to provide another approach of STAR data analysis. Our results show there exists an NΩ “bound” state, which can be observed by the N−Ω correlation analysis with RHIC and LHC data, or by the new developed automatic scanning system at J-PARC. In addition, we also find that the hidden-color channel coupling is important for the NΩ system to develop intermediate-range attraction.

关键词： DIBARYON QUARK models PHASE shift (Nuclear physics) QUANTUM chromodynamics QUARK-gluon plasma

The effects of KSEA interaction on the ground-state properties of spin chains in a transverse field

学校读者我要写书评

暂无评论

arXiv 2019年

作者： Fu, Hao Zhong, Ming 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 effects of symmetric helical interaction which is called the Kaplan, Shekhtman, Entin-Wohlman, and Aharony (KSEA) interaction on the ground-state properties of three kinds of spin chains in a transverse field have been studied by means of correlation functions and chiral order parameter. We find that the anisotropic transition of XY chain in a transverse field (XY TF) disappears because of the KSEA interaction. For the other two chains, we find that the regions of gapless chiral phases in the parameter space induced by the DM or XZY -Y ZX type of three-site interaction are decreased gradually with increase of the strength of KSEA interaction. When it is larger than the coefficient of DM or XZY - Y ZX type of three-site interaction, the gapless chiral phases also disappear. Copyright © 2019, The Authors. All rights reserved.

关键词： Spin dynamics

B→ππ decays and effects of the next-to-leading order contributions

学校读者我要写书评

暂无评论

Physical Review D 2014年第1期90卷 014029-014029页

作者： Ya-Lan Zhang Xue-Yan Liu Ying-Ying Fan Shan Cheng Zhen-Jun Xiao Department of Physics and Institute of Theoretical Physics Nanjing Normal University Nanjing Jiangsu 210023 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 perform a systematic study for the three B→(π+π−,π+π0,π0π0) decays in the perturbative QCD (pQCD) factorization approach with the inclusion of all currently known next-to-leading order (NLO) contributions from various sources. We found that (a) for the CP-averaged decay rates Br(B0→π+π−) and Br(B+→π+π0), the NLO pQCD predictions agree with the data within one standard deviation; (b) for Br(B0→π0π0), however, although the NLO contributions can provide a ∼100% enhancement to the leading-order (LO) result, it is still not large enough to interpret the data; and (c) for the CP-violating asymmetries of B0→π+π− decay, the NLO pQCD predictions for the central values of Aππ and Sππ have the same sign as the data but are still smaller in magnitude than the measured values. We also examined the relative strength of the LO and NLO contributions from different sources.

关键词：

Influences of weak disorder on dynamical quantum phase transitions of anisotropic XY chain

学校读者我要写书评

暂无评论

arXiv 2019年

作者： Cao, Kaiyuan Li, Wenwen Zhong, Ming 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

In this paper, the effects of disorder on the dynamical quantum phase transitions (DQPTs) in the transverse-field anisotropic XY chain are studied by numerically calculating the Loschmidt echo after quench. We obtain the formula for calculating the Loschmidt echo of the inhomogeneous system in real space. By comparing the results with that of the homogeneous chain, we find that when the quench crosses the Ising transition, the small disorder will cause a new critical point. As the disorder increases, more critical points of the DQPTs will occur, constituting a critical region. In the quench across the anisotropic transition, the disorder will cause a critical region near the critical point, and the width of the critical region increases by the disordered strength. In the case of quench passing through two critical lines, the small disorder leads to the system to have three additional critical points. When the quench is in the ferromagnetic phase, the large disorder causes the two critical points of the homogeneous case to become a critical region. And for the quench in the paramagnetic phase, the DQPTs will disappear for large disorder. Copyright © 2019, The Authors. All rights reserved.

关键词： Phase transitions

Clifford algebra-based spatio-temporal modelling and analysis for complex geo-simulation data

学校读者我要写书评

暂无评论

AIP Conference Proceedings 2013年第1期1558卷 542-545页

作者： Wen Luo Zhaoyuan Yu Yong Hu Linwang Yuan Key Laboratory of Virtual Geographic Environment Ministry of Education Nanjing Normal University No.1 Wenyuan Road Nanjing China Key Laboratory of Virtual Geographic Environment Ministry of Education Nanjing Normal University No.1 Wenyuan Road Nanjing China and Jiangsu Provincial Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal Univer China

The spatio-temporal data simulating Ice-Land-Ocean interaction of Antarctic are used to demonstrate the Clifford algebra-based data model construction, spatio-temporal query and data analysis. The results suggest that Clifford algebra provides a powerful mathematical tool for the whole modelling and analysis chains for complex geo-simulation data. It can also help implement spatio-temporal analysis algorithms more clearly and simply.

关键词：

Theoretical study of a d* resonance in the coupled 3D3−3G3 partial waves of nucleon-nucleon scattering

学校读者我要写书评

暂无评论

Physical Review C 2014年第6期90卷 064003-064003页

作者： Hongxia Huang Jialun Ping Chengrong Deng Fan Wang Department of Physics and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210023 China School of Mathematics and Physics Chongqing Jiaotong University Chongqing 400074 China Department of Physics Nanjing University Nanjing 210093 China

We calculated the phase shifts of the coupled 3D3−3G3 partial waves of nucleon-nucleon scattering taking into account the 7S3 Δ−Δ channel coupling in the framework of two constituent quark models: the quark delocalization color screening model and the chiral quark model. Our results show that there is a resonance from 7S3ΔΔ coupling to the 3D3NN and 3G3NN partial waves in both of these two models, which is consistent with the d* resonance observed by WASA-at-COSY collaboration. The resonance structure in the 3D3NN partial wave is remarkable, whereas in the 3G3NN phase shifts there is only a small bump around the resonance energy. This result is in agreement with the recent experimental results of WASA-at-COSY Collaboration.

关键词： NUCLEON-nucleon scattering NEUTRON resonance QUARK models DELOCALIZATION energy QUANTUM chromodynamics

Quasi-two-body decays B(s) → Pp'(1450), Pp'(1700) Pππ in the perturbative QCD approach

学校读者我要写书评

暂无评论

arXiv 2017年

作者： Li, Ya Ma, Ai-Jun Wang, Wen-Fei Xiao, Zhen-Jun Institute of Theoretical Physics Shanxi University Taiyuan Shanxi030006 Department of Physics Institute of Theoretical Physics Nanjing Normal University Nanjing Jiangsu210023 Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing Jiangsu210023

In this work, we calculate the CP-averaged branching ratios and direct CP-violating asymmetries of the quasi-two-body decays B(s) → P'(1450), Pp'(1700) → Pππ by employing the perturbative QCD (PQCD) factorization approach, where P is a light pseudoscalar meson K, π, n, and n'. The considered decay modes are studied in the quasi-two-body framework by parametrizing the two-pion distribution amplitude P ππ. The P-wave timelike form factor Fπ in the resonant regions associated with the pp'(1450) and p'(1700) is estimated based on available experimental data. The PQCD predictions for the CP-averaged branching ratios of the decays B(s) → Pp'(1450) pp'(1700) → Pππ are in the order of 10-7-10-9. The branching ratios of the two-body decays B(s) → Pp'(1450), Pp'(1700) are extracted from the corresponding quasi-twobody decay modes. The whole pattern of the squared pion form factor |Fπ|2 measured by BABAR Collaboration could also be understood based on our studies. The PQCD predictions in this work will be tested by the precise data from the LHCb and the future Belle II experiments. Copyright © 2017, The Authors. All rights reserved.

关键词： Hadrons

Effects of infinite-range interaction on the localization properties of one-dimensional disordered harmonic chains

学校读者我要写书评

暂无评论

Physical Review B 2023年第2期108卷 024202-024202页

作者： Wanwan Shi Peiqing Tong School of Physics and Technology Nanjing Normal University Nanjing 210023 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 and Nanjing Normal University Taizhou College Taizhou 225300 People's Republic of China

We study the effects of infinite-range (IR) interaction on the localization properties of one-dimensional disordered harmonic chains. Two kinds of disordered models are considered: one is with disordered masses, but constant spring coefficient (mass model), and the other is with disordered spring coefficient, but constant mass (spring model). It is found that the IR interaction induces a gap between the ω=0 and the excited frequency band for both types of disordered models, and their gaps are both proportional to the IR interaction coefficient γ for larger γ. In addition, the width of the excited frequency band of the mass model is also proportional to γ for larger γ, while that of the spring model is independent of γ. By employing the normalized participation ratio, we find that the low-frequency modes of the mass model except for the lowest frequency change from extended to localized states, while the localized properties of the spring model modes remain unchanged. We also discuss the effects of IR interaction on the dynamic behaviors of the two kinds of disordered models.

关键词： Lattice dynamics Localization Long-range interactions Phonons 1-dimensional systems Disordered systems