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Quantum Phase Transitions in the Alternating Xy Chain with Three-Site Interactions

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SSRN

SSRN 2024年

作者： Cao, Kaiyuan Fu, Hao Liu, Xue Zhong, Ming Tong, Peiqing 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

We investigate the quantum phase transition in the alternating XY chain with the XZX+YZY type of three-spin interactions. We present the exact solution derived by means of the Jordan-Wigner transformation and study the average magnetization, spin correlations, and von Neumann entropy to establish the phase diagram. The phase diagram consists of the ferromagnetic phases, the paramagnetic phases, and the phase with weak magnetization (WM). By examining the nearest-neighbor transverse spin correlation, we probe that in the WM phase, the spins within a supercell generate a cluster with a small total spin, but between the nearest-neighbor supercells are distributed randomly. Especially for the dimerized limit case, the spins within a supercell tend to point to opposite directions of the transverse field. In addition, we also investigate the influence of the three-site interaction, and find that the WM phase is absent as the strength of the three-site interaction increases. © 2024, The Authors. All rights reserved.

关键词： Magnetization

Exploring Dynamical Phase Transitions in the XY Chain through Linear Quench: Early and Long-term Perspectives

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arXiv 2024年

作者： Cao, Kaiyuan Tong, Peiqing 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

We investigate the nonequilibrium dynamics induced by a finite-time linear quench in the XY chain. Initially, we examine the dynamical quantum phase transition, characterized by the nonanalytic behavior of the Loschmidt amplitude. We find distinct behaviors of DQPTs during and following the ramp. Following the ramp, the ramp crossing the critical point hc is the sufficient condition for the occurrence of DQPT, but it is not during the ramp. Through AIA approximation analysis, we establish that adequate distancing from the critical point is crucial for DQPT manifestation during the ramp, elucidating the absence of DQPT as the ramp gets faster. Additionally, we explore another type of dynamical phase transition, describing the long-term relaxation behavior of the order parameter. Our finding indicates that the asymptotic behavior of the time-dependent part induced by the linear quench is equivalent to that following a sudden quench, i.e., time-dependent part exhibits power-law decays of ∼ t−3/2 and ∼ t−1/2 for the ramp to the commensurate and incommensurate phases, respectively. Moreover, we also delve into the steady part, which showcases nonanalytic singularities at the critical point. Copyright © 2024, The Authors. All rights reserved.

关键词： Phase transitions

Quantum phase transitions in the alternating XY chain with three-site interactions

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arXiv 2024年

关键词： Magnetization

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

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Physical Review D 2017年第3期96卷 036014-036014页

作者： Ya Li Ai-Jun Ma Wen-Fei Wang Zhen-Jun Xiao Department of Physics and Institute of Theoretical Physics Nanjing Normal University Nanjing Jiangsu 210023 People’s Republic of China Institute of Theoretical Physics Shanxi University Taiyuan Shanxi 030006 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing Jiangsu 210023 People’s Republic of China

In this work, we calculate the CP-averaged branching ratios and direct CP-violating asymmetries of the quasi-two-body decays B(s)→Pρ′(1450),Pρ′′(1700)→Pππ by employing the perturbative QCD (PQCD) factorization approach, where P is a light pseudoscalar meson K, π, η, and η′. The considered decay modes are studied in the quasi-two-body framework by parametrizing the two-pion distribution amplitude ΦππP. The P-wave timelike form factor Fπ in the resonant regions associated with the ρ′(1450) and ρ′′(1700) is estimated based on available experimental data. The PQCD predictions for the CP-averaged branching ratios of the decays B(s)→Pρ′(1450),Pρ′′(1700)→Pππ are in the order of 10−7−10−9. The branching ratios of the two-body decays B(s)→Pρ′(1450),Pρ′′(1700) are extracted from the corresponding quasi-two-body 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.

关键词： Branching fraction Hadronic decays

Quasi-two-body decays B(s)→Pρ→Pππ in the perturbative QCD approach

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Physical Review D 2017年第5期95卷 056008-056008页

In this work, we calculate the CP-averaged branching ratios and the direct CP-violating asymmetries of the quasi-two-body decays B(s)→P(ρ→)ππ by employing the perturbative QCD (PQCD) approach (here P stands for a light pseudoscalar meson π, K, η or η′). The vector current timelike form factor Fπ, which contains the final-state interactions between the pion pair in the resonant region associated with the P-wave states ρ(770) along with the two-pion distribution amplitudes, is employed to describe the interactions between the ρ and the pion pair under the hypothesis of the conserved vector current. We found that (a) the PQCD predictions for the branching ratios and the direct CP-violating asymmetries for most considered B(s)→P(ρ→)ππ decays agree with currently available data within errors, (b) for B(B→π0ρ0→π0(π+π−), the PQCD prediction is much smaller than the measured one, and (c) for the B+→π+(ρ0→)π+π− decay mode, there is a negative CP asymmetry (−27.5−3.7+3.0)%, which agrees with other theoretical predictions but is different in sign from those reported by the BABAR and LHCb Collaborations.

关键词： Branching fraction Hadronic decays

Anatomy of Bs → P V decays and effects of next-to-leading order contributions in the perturbative QCD factorization approach

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arXiv 2017年

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

In this paper, we will make systematic calculations for the branching ratios and the CP-violating asymmetries of the twenty one B¯s0 → P V decays by employing the perturbative QCD (PQCD) factorization approach. Besides the full leading-order (LO) contributions, all currently known next-to-leading order (NLO) contributions are taken into account. We found numerically that: (a) the NLO contributions can provide ∼ 40% enhancement to the LO PQCD predictions for B(B¯s0 → K0K¯ ∗0) and B(B¯s0 → K±K∗), or a ∼ 37% reduction to B(B¯s0 → π−K∗+);and we confirmed that the inclusion of the known NLO contributions can improve significantly the agreement between the theory and those currently available experimental measurements;(b) the total effects on the PQCD predictions for the relevant B → P transition form factors after the inclusion of the NLO twist-2 and twist-3 contributions is generally small in magnitude: less than 10% enhancement respect to the leading order result;(c) for the "tree" dominated decay B¯s0 → K+ρ− and the "color-suppressed-tree" decay B¯s0 → π0K∗0, the big difference between the PQCD predictions for their branching ratios are induced by different topological structure and by interference effects among the decay amplitude AT,C and AP: constructive for the first decay but destructive for the second one;and (d) for B¯s0 → V (η, η′) decays, the complex pattern of the PQCD predictions for their branching ratios can be understood by rather different topological structures and the interference effects between the decay amplitude A(V ηq) and A(V ηs) due to the η − η′ mixing. Copyright © 2017, The Authors. All rights reserved.

关键词： Forecasting

Resonance contributions from χc0 in the charmless three-body hadronic B meson decays

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arXiv 2023年

作者： Zhang, Ya-Lan Wang, Chao Lin, Yi Xiao, Zhen-Jun Faculty of Mathematics and Physics Huaiyin Institute of Technology Jiangsu Huaian223200 China Department of Physics Institute of Theoretical Physics Nanjing Normal University Jiangsu Nanjing210023 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Jiangsu Nanjing210023 China

Within the framework of perturbative QCD factorization, we investigate the nonfactorizable contributions to these factorization-forbidden Quasi-two-body decays B(s) → hχc0 → hπ+π−(K+K−) with h = π,K. We compare our predicted branching ratios for the B(s) → Kχc0 → Kπ+π−(K+K−) decay with available experiment data as well as predictions by other theoretical studies. The branching ratios of these decays are consistent with data and other theoretical predictions. In the Cabibbo-suppressed decays B(s) → hχc0 → hπ+π−(K+K−) with h = K¯0,π, however, the values of the branching ratios are the order of 10−7 and 10−8. The ratio Rχc0 between the decay B+ → π+χc0 → π+π+π− and B+ → K+χc0 → K+π+π− and the distribution of branching ratios for different decay modes in invariant mass are considered in this work. © 2023, CC BY.

关键词： Factorization

Anatomy of Bs → V V decays and effects of next-to-leading order contributions in the perturbative QCD factorization approach

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arXiv 2018年

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

By employing the perturbative QCD (PQCD) factorization approach, we calculated the branching ratios, CP-violating asymmetries, the longitudinal and transverse polarization fractions and other physical observables of the thirteen charmless hadronic B¯s0 → V V decays with the inclusion of all currently known next-to-leading order (NLO) contributions. We focused on the examination of the effects of all those currently known NLO contributions and found that: (a) for the measured decays B¯s0 → φφ, K∗0φ, K¯ ∗0K∗0 and ρ0φ, the NLO contributions can provide ∼ 20% to ∼ 40% enhancements to the leading order (LO) PQCD predictions of their CP-averaged branching ratios, and consequently the agreement between the PQCD predictions and the measured values are improved effectively after the inclusion of the NLO contributions;(b) for the measured decays, the NLO corrections to the LO PQCD predictions for (fL, f) and (φk, φ) are generally small in size, but the weak penguin annihilation contributions play an important role in understanding the data about their decay rates, fL and f;(c) the NLO PQCD predictions for above mentioned physical observables do agree with the measured ones and the theoretical predictions from the QCDF, SCET and FAT approaches;(d) for other considered Bs0 → V V decays, the NLO PQCD predictions for their decay rates and other physical observables are also basically consistent with the theoretical predictions from other popular approaches, future precision measurements could help us to test or examine these predictions. Copyright © 2018, The Authors. All rights reserved.

关键词： Forecasting

Possible existence of a dibaryon candidate N▵ (D21)

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arXiv 2018年

作者： Huang, Hongxia Zhu, Xinmei Ping, Jialun Wang, Fan Dept. of Physics and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 China Department of Physics Yangzhou University Yangzhou225009 China Department of Physics Nanjing University Nanjing210093 China

Inspired by the experimental report by WASA-at-COSY Collaboration, we investigate the possibile existence of the dibaryon candidate N▵ with quantum numbers IJP= 21+(D21). The dynamical calculation shows that we cannot obtain the bound D21 state in the models which can obtain the experimental d. The low-energy scattering phase shifts of the N-▵ scattering give the same conclusion. Besides, the mass calculation by using the Gursey-Radicati mass formula and the analysis of the matrix elements of the color magnetic interaction show that the mass of D21is larger than that of D12(N▵ with IJP= 12+), which indicate that it is less possible for the D21than the D12to form bound state. Copyright © 2018, The Authors. All rights reserved.

关键词： Quantum theory