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Chirped Bright and Kink Solitons in Nonlinear Optical Fibers with Weak Nonlocality and Cubic-Quantic-Septic Nonlinearity

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Chinese physics Letters 2022年第4期39卷 12-16页

作者： Qin Zhou Yu Zhong Houria Triki Yunzhou Sun Siliu Xu Wenjun Liu Anjan Biswas Research Center of Nonlinear Science School of Mathematical and Physical SciencesWuhan Textile UniversityWuhan 430200China Radiation Physics Laboratory Department of PhysicsFaculty of SciencesBadji Mokhtar UniversityP.O.Box 1223000 AnnabaAlgeria School of Electronic and Information Engineering Hubei University of Science and TechnologyXianning 437100China State Key Laboratory of Information Photonics and Optical Communications School of ScienceBeijing University of Posts and TelecommunicationsBeijing 100876China Beijing University of Posts and Telecommunications Research Institute Shenzhen 518057China Department of Physics Chemistry and MathematicsAlabama A&M UniversityNormalAL 35762-4900USA Mathematical Modeling and Applied Computation(MMAC)Research Group Department of MathematicsKing Abdulaziz UniversityJeddah 21589Saudi Arabia

This work focuses on chirped solitons in a higher-order nonlinear Schrodinger equation,including cubic-quinticseptic nonlinearity,weak nonlocal nonlinearity,self-frequency shift,and self-steepening *** the first time,analytical bright and kink solitons,as well as their corresponding chirping,are *** influence of septic nonlinearity and weak nonlocality on the dynamical behaviors of those nonlinearly chirped solitons is thoroughly *** findings of the study give an experimental basis for nonlinear-managed solitons in optical fibers.

关键词： effect nonlinearity solitons

There and Back Again: Mapping and Factorizing Cosmological Observables

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Physical Review Letters 2024年第22期133卷 221501-221501页

作者： David Stefanyszyn Xi Tong Yuhang Zhu School of Mathematical Sciences and School of Physics and Astronomy University of Nottingham University Park Nottingham NG7 2RD United Kingdom Department of Applied Mathematics and Theoretical Physics University of Cambridge Wilberforce Road Cambridge CB3 0WA United Kingdom Cosmology Gravity and Astroparticle Physics Group Center for Theoretical Physics of the Universe Institute for Basic Science Daejeon 34126 Korea

Cosmological correlators encode invaluable information about the wave function of the primordial Universe. In this Letter we present a duality between correlators and wave function coefficients that is valid to all orders in the loop expansion and manifests itself as a Z4 symmetry. To demonstrate the power of the duality, we derive a correlator-to-correlator factorization formula for the parity-odd part of cosmological correlators that relates n-point observables to lower-point ones via a series of diagrammatic cuts. These relations serve as the first example of physically testable cutting rules as they involve observables defined for arbitrary physical kinematics. We further show how the duality allows us to translate the cosmological optical theorem for wave function coefficients into statements about cosmological correlators.

关键词： Effective field theory Inflation Quantum cosmology Quantum fields in curved spacetime P-symmetry Parity

Large non-reciprocal charge transport in Pt2MnGe up to room temperature

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arXiv 2022年

作者： Meng, Kangkang Wang, K. Zhang, N.N. Fu, Z.G. Chen, J.K. Wu, Y. Xu, X.G. Miao, J. Jiang, Y. School of Materials Science and Engineering University of Science and Technology Beijing Beijing100083 China Institute of Applied Physics and Computational Mathematics Beijing China

Non-reciprocal charge transport that is strongly associated with the structural or magnetic chirality of the quantum materials system is one of the most exotic properties of condensed matter physics. Here, using magnetic alloys film Pt2MnGe, we have realized the large non-reciprocal charge transport up to room temperature, which roots in the organic combination of chirality dependent carrier scattering and special magnetic configurations. In this framework, the conduction electrons are scattered asymmetrically by the emerging non-zero vector spin chirality under in-plane magnetic field, resulting in robust non-reciprocal response. More astonishingly, the vector spin chirality in Pt2MnGe film can be reversed by a spin-polarized current through spin Hall effect in a junction with Pt layer. Our work resolves the general limitation of non-reciprocal charge transport to cryogenic temperatures, and paves the way for extending its applications in the emerging field of chiral spintronics. © 2022, CC BY.

关键词： Quantum chemistry

Prediction of ambient-pressure superconductivity in the perovskite hydrides MScH3(M=K,Rb,Cs)

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Physical Review B 2025年第13期111卷 134509-134509页

作者： Hao Quan Xian-Biao Shi Yu-Lin Han Ping Zhang Bao-Tian Wang Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China Institute of Theoretical Physics State Key Laboratory of Quantum Optics and Quantum Optics Devices Collaborative Innovation Center of Extreme Optics Shanxi University Taiyuan 030006 China Spallation Neutron Source Science Center Dongguan 523803 China School of Physics and Physical Engineering Qufu Normal University Qufu 273165 China Institute of Applied Physics and Computational Mathematics Beijing 100088 China

Cubic perovskite hydrides with the general formula of MXH3 have recently been predicted to have the potential to achieve superconductivity at ambient pressure. Here, based on first-principles calculations as well as the BCS theory, we propose that replacing the Mg in KMgH3, which is an experimentally synthesized cubic perovskite hydride exhibiting insulating behavior, with Sc can give rise to a mechanically, dynamically, and kinetically stable superconductor, KScH3. Its superconducting transition temperature (Tc) is up to 40.37 K at ambient pressure. Further substitution of the K in KScH3 with Rb and Cs leads to structurally stable RbScH3 and CsScH3, with Tc's of 32.91 and 18.64 K, respectively. Electron-phonon coupling calculations reveal that the soft modes in the intermediate-frequency region associated with the vibrations of H atoms in the phonon spectra play a non-negligible role in determining the high Tc's of MScH3 (M = K, Rb, Cs). All these three perovskite hydrides are intermediate or strong BCS superconductors. Our results provide guidance for the design and study of ambient-pressure hydride superconductors and supply fundamental understanding of the superconductivity physical mechanism.

关键词： Perovskite

Comment on “Stark shift and width of x-ray lines from highly charged ions in dense plasmas”

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Physical Review A 2022年第5期105卷 056801-056801页

作者： T. N. Chang Xiang Gao Department of Physics University of Southern California Los Angeles California 90089-0484 USA Institute of Applied Physics and Computational Mathematics Beijing 100088 China Beijing Computational Science Research Center Beijing 100193 China

We point out in this Comment a misleading remark made by Gu and Beiersdorfer [Phys. Rev. A 101, 032501 (2020)] that the Debye-Hückel (DH) model “performs rather poorly” compared with the ion sphere model is due to their questionable use of the Debye length by assuming the same mobility for the plasma electrons and ions. Actually, our recent works based on a judicious application of the DH approximation, which meets the spatial and temporal criteria, have led to good agreements with all the available line shift experimental measurements on α and β emission lines of He-like ions.

关键词： Electronic structure of atoms & molecules Stark effect

MRCI+Q calculations on electronic structure and spectroscopy of low-lying electronic states of silicon monobromide including spin-orbit coupling effect

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Journal of Quantitative Spectroscopy and Radiative Transfer 2024年 329卷

作者： Li, Rui Gu, Xinyu Lin, Xiaohe Wu, Yong Department of Physics College of Science Qiqihar University Qiqihar161006 China College of Teacher Education Qiqihar University Qiqihar161006 China Faculty of Foundation Space Engineering University Beijing 101416 China National Key Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics P. O. Box 8009 Beijing 100088 China HEDPS Center for Applied Physics and Technology Peking University Beijing 100084 China School of Physics and Information Technology Shaanxi Normal University Xi'an710119 China

The electronic structures of silicon monobromide (SiBr) correlating with the lowest three dissociation channels are studied using high-level configuration interaction method. The spin-orbit coupling (SOC) effect and core-valence (CV) correlations effect are taken into account to improve the accuracy of electronic structures. Based on the calculated electronic structures of the lowest three dissociation channels of SiBr, the spectroscopic constants of quasibound and bound electronic states are fitted, which are coincided with the results of experiment. The dipole moment curves (DMs) of the lowest three dissociation channels of SiBr are obtained, and the abrupt change of DMs nearby the avoided crossing point are explained by the variation of electronic configurations of the corresponding states. With the help of the calculated SOC matrix elements, the predissociation channels of the low-lying vibrational states of 2Δ(Ⅱ) and 2Π(Ⅲ) sates are analyzed. The complicated interaction between crossing states is investigated. The ν'≥0 vibrational states of 2Δ(Ⅱ) and ν′≥2 vibrational states of 2Π(Ⅲ) would predissociate rapidly through predissociation channels of 2Δ(Ⅱ)-2Π(Ⅱ) and 2Π(Ⅲ)-2Σ+(Ⅱ). Finally, the transition properties of A2Σ+-X2Π, 2∆(Ⅱ)-X2Π, 2Σ+(Ⅱ)-X2Π, 2Π(Ⅲ)-X2Π, 1/2(Ⅱ)-X2Π1/2, 1/2(Ⅲ)-X2Π1/2 and 3/2(Ⅱ)-X2Π1/2 transitions are investigated, and radiative lifetime of bound states are evaluated. © 2024 Elsevier Ltd

关键词： Spin orbit coupling

The Fe-Ni phase diagram and the Earth’s inner core structure

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arXiv 2025年

作者： Wei, Liangrui Ho, Kai-Ming Wentzcovitch, Renata M. Sun, Yang Department of Physics Xiamen University Xiamen361005 China Department of Physics Iowa State University AmesIA50011 United States Department of Applied Physics and Applied Mathematics Columbia University New YorkNY10027 United States Department of Earth and Environmental Sciences Columbia University New YorkNY10027 United States Lamont–Doherty Earth Observatory Columbia University Palisades NY10964 United States Data Science Institute Columbia University New YorkNY10027 United States

The Fe-Ni alloy is believed to be the main component of Earth’s core. Yet, a comprehensive understanding of phase equilibria near the melting point of this alloy under core conditions is still lacking, leaving the effect of nickel inconclusive. Using ab initio simulations, we computed Gibbs free energy and phase diagram for liquid and solid solutions of the Fe-Ni alloy under conditions close to the inner core, considering inner-shell electron contributions and non-ideal mixing effects. The Fe-Ni phase diagram provides crucial insights for understanding previous experimental observations and crystallization simulations of the Fe-Ni alloy under core conditions. It also presents new scenarios for inner core structures, suggesting bcc-liquid coexistence at the inner core boundary and the possibility of multi-layer structures consisting of bcc-hcp composites within the inner core. Our work clarifies nickel’s substantial impact on the inner core structure, providing new constraints for the study of core’s composition and formation. Copyright © 2025, The Authors. All rights reserved.

关键词： Gibbs free energy

Asymptotic stability of the equilibrium for the free boundary problem of a compressible atmospheric primitive model with physical vacuum

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arXiv 2024年

作者： Liu, Xin Titi, Edriss S. Xin, Zhouping Department of Mathematics Texas A&M University College StationTX77843-3368 United States Department of Mathematics Texas A&M University College StationTX77843-3368 United States Department of Applied Mathematics and Theoretical Physics University of Cambridge CambridgeCB3 0WA United Kingdom Department of Computer Science and Applied Mathematics Weizmann Institute of Science Rehovot76100 Israel The Institute of Mathematical Sciences The Chinese University of Hong Kong New Territories Shatin Hong Kong

This paper concerns the large time asymptotic behavior of solutions to the free boundary problem of the compressible primitive equations in atmospheric dynamics with physical vacuum. Up to second order of the perturbations of an equilibrium, we have introduced a model of the compressible primitive equations with a specific viscosity and shown that the physical vacuum free boundary problem for this model system has a global-in-time solution converging to an equilibrium exponentially, provided that the initial data is a small perturbation of the equilibrium. More precisely, we introduce a new coordinate system by choosing the enthalpy (the square of sound speed) as the vertical coordinate, and thanks to the hydrostatic balance, the degenerate density at the free boundary admits a representation with separation of variables in the new coordinates. Such a property allows us to establish horizontal derivative estimates without involving the singular vertical derivative of the density profile, which plays a key role in our *** Codes 35Q35, 76E20, 76N10, 86A10 © 2024, CC BY.

关键词： Viscosity

Robustness test of the spacegroupMining model for determining space groups from atomic pair distribution function data

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arXiv 2022年

作者： Lan, Ling Liu, Chia-Hao Du, Qiang Billinge, Simon J. L. Department of Applied Physics and Applied Mathematics Columbia University New YorkNY10027 United States Data Science Institute Columbia University New YorkNY10027 United States Condensed Matter Physics and Materials Science Department Brookhaven National Laboratory Uptown NY11973 United States

Machine learning models based on convolutional neural networks have been used for predicting space groups of crystal structures from their atomic pair distribution function (PDF). However, the PDFs used to train the model are calculated using a fixed set of parameters that reflect specific experimental conditions, and the accuracy of the model when given PDFs generated with different choices of these parameters is unknown. In this paper, we report that the results of the top-1 accuracy and top-6 accuracy are robust when applied to PDFs of different choices of experimental parameters rmax, Qmax, Qdampand atomic displacement parameters. © 2022, CC BY.

关键词： Convolutional neural networks