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Kerr black hole shadows cast by extraordinary light rays with Weyl corrections

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 18-26页

作者： Songbai Chen Jiliang Jing Department of Physics Institute of Interdisciplinary StudiesKey Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of EducationSynergetic Innovation Center for Quantum Effects and ApplicationsHunan Normal UniversityChangsha 410081China center for Gravitation and Cosmology College of Physical Science and TechnologyYangzhou UniversityYangzhou 225009China

We investigate the equation of motion for photons with Weyl corrections in a Kerr black hole spacetime in a small coupling case.Our results show that Weyl corrections yield phenomena of birefringence.The light rays propagating in the spacetime are separated into the ordinary rays and the extraordinary rays,and the propagation of the latter depends on the corrections.We probe the effects of Weyl corrections on the Kerr black hole shadows casted by the extraordinary rays and find that such corrections result in a weak stretching or squeezing in the vertical direction for the black hole shadows.Finally,we also study the change of the length of the Near-Horizon Extremal Kerr line(NHEK line)with Weyl corrections.These features could help us to understand the electrodynamics with Weyl corrections from black hole shadows.

关键词： correction light stretching

Quantum phase transition of the Jaynes-Cummings model

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Science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 1-9页

作者： Cheng Liu Jin-Feng Huang Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Key Laboratory for Matter Microstructure and Function of Hunan ProvinceDepartment of Physics and Synergetic Innovation Center for Quantum Effects and ApplicationsInstitute of Interdisciplinary StudiesHunan Normal UniversityChangsha 410081China

Herein,we propose an experimentally feasible scheme to show the quantum phase transition of the Jaynes-Cummings(JC)model by modulating the transition frequency of a two-level system in a quantum Rabi model with strong coupling.By tuning the modulation frequency and amplitude,the ratio of the effective coupling strength of the rotating terms to the effective cavity(atomic transition)frequency can enter the deep-strong coupling regime,while the counter-rotating terms can be neglected.Thus,a deep-strong JC model is obtained.The ratio of the coupling strength to resonance frequencies in the deep-strong JC model is two orders of magnitude larger than the corresponding ratio in the original quantum Rabi model.Our scheme can be employed in atom-cavity resonance and off-resonance cases,and it is valid over a broad range.The nonzero average cavity photons of the ground state indicate the emergence of a quantum phase transition.Further,we demonstrate the dependence of the phase diagram on the atom-cavity detuning and modulation parameters.All the parameters used in our scheme are within the reach of current experimental technology.Our scheme provides a new mechanism for investigating the critical phenomena of finite-sized systems without requiring classical field limits,thereby opening a door for studying fundamental quantum phenomena occurring in the ultrastrong and even deep-strong coupling regimes.

关键词： Jaynes-Cummings model quantum phase transition frequency modulation

High-lattice-adapted surface modifying Na_(4)MnV(PO_(4))_(3) for better sodium storage

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Nano Research 2024年第4期17卷 2728-2735页

作者： Chongran Song Shiyu Li Ying Bai International Joint Research Laboratory of New Energy Materials and Devices of Henan Province School of Physics and ElectronicsAcademy for Advanced Interdisciplinary StudiesHenan UniversityKaifeng 475004China

Sodium-ion batteries(SIBs)are required to possess long cycle life when used for large-scale energy storage.The polyanionic Na_(4)MnV(PO_(4))_(3)(NMVP)reveals good cyclic stability due to its unique three-dimensional(3D)frame structure,but it still faces the challenge of interfacial degradation in practical applications.In this work,NASICON-type Na_(1.3)Al_(0.7)Ti_(1.3)(PO_(4))_(3)(NATP)was deposited on the surface of NMVP to promote interface stability by surface modification and gradient doping.As a result,the optimized NMVP@2%NATP released a capacity retention of 44.8%after 1000 cycles at 5 C,much higher than that of the initial NMVP(28.9%).The enhanced electrochemical performance was mainly attributed to NATP coating acting as a fast ion transport carrier and physical barrier,significantly facilitating the Na^(+)diffusion and isolating side reaction at the electrode/electrolyte interface.On the other hand,Ti_(4)^(+)and Al^(3+)cations from the NATP were partially doped inside the NMVP surface to boost the transport of Na^(+),and the perfect lattice matching of NVMP and NATP improved the interface and structural stability accompanying long cycling.This work demonstrated the effectiveness of surface modification with high lattice match material and provided new perspectives for high energy density solid-state SIBs.

关键词： high-lattice-adapted cathode surface modification sodium-ion batteries

Graphene/Molybdenum Dichalcogenide-Based van der Waals Heterostructure Photodetectors: a Review

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新型炭材料(中英文) 2024年

作者： ZHANG Xin-hua LIU Wei-Di GONG You-pin LIU Qing-feng CHEN Zhi-Gang center of Quantum Materials and Devices at Institute of Advanced interdisciplinary studies Soft Matter and Interdisciplinary Research Center College of Physics Chongqing University School of Chemistry and Physic ARC Research Hub in Zero-emission Power Generation for Carbon Neutrality and Center for Materials Science Queensland University of Technology State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemical Engineering Nanjing Tech University

Graphene is widely used in photodetection due to its high carrier mobility and wide spectral absorption range.However, the high dark current due to its low light absorption severely limits the performance of photodetection. Molybdenum dihalide(MoX2, X= S, Se and Te) has a high absorption coefficient, which can compensate high dark current in graphene-based photodetectors and result in outstanding photoelectronic properties in graphene/MoX2 van der Waals heterostructure(vdWH) photodetectors.In this review, we firstly review working principles, performance indicators, and structures of photodetectors. After that, the significance of graphene/MoX2 vdWH photodetectors are highlighted from the material fundamental perspective. Preparation methodologies and performance enhancement strategies of graphene/MoX2 vdWH photodetectors are correspondingly summarized. In the end, we highlight the current challenges and future directions of the graphene/MoX2 vdWH photodetectors. This review will guide the design of high-performance vdWH photodetectors.

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Merger estimates for a disformal Kerr black hole in quadratic degenerate higher-order scalar-tensor theories

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Chinese Physics C 2024年第5期48卷 284-292页

作者：蒋洪鑫杜欣怡潘启沅陈松柏荆继良 Key Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of Education Synergetic Innovation Center for Quantum Effects and Applicationsand Department of PhysicsHunan Normal UniversityChangsha 410081China Institute of interdisciplinary studies Hunan Normal UniversityChangsha 410081China center for Gravitation and Cosmology College of Physical Science and TechnologyYangzhou UniversityYangzhou 225009China

We investigate the main features of a disformal Kerr black hole merger in quadratic degenerate higher-order scalar-tensor theories.In the ringdown stage of the black hole merger,for the prograde orbit,the real part of the quasinormal modes decreases with an increase in the disformal parameter,and the imaginary part also decreases,except in the Kerr case for a large spin parameter.However,for the retrograde orbit,the real part increases with an increase in the disformal parameter,and the imaginary part always decreases with it.For the approximate final spin,regardless of an equal spin,unequal spin,or generic spin configuration merger,the final black hole spin always increases with an increase in the disformal parameter.Our results show that the disformal parameter in the disformal Kerr solution and the MOG parameter in the Kerr-MOG case have obviously different effects on the black hole merger,which suggests the differences between these two spacetime structures.

关键词： black hole merger quasinormal modes final black hole spin disformal Kerr black hole quadratic degenerate higher-order scalar-tensor(DHOST)theory

Chiral bound states in a staggered array of coupled resonators

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Chinese Physics B 2024年第2期33卷 124-130页

作者：金伍林李静卢竞龚志瑞周兰 Synergetic Innovation center for Quantum Effects and Applications Key Laboratory for Matter Microstructure and Function of Hunan ProvinceKey Laboratory of Low-Dimensional Quantum Structures and Quantum Control of the Ministry of EducationSynergetic Innovation Center for Quantum Effects and ApplicationsInstitute of Interdisciplinary StudiesXiangjiang-Laboratory and Department of PhysicsHunan Normal UniversityChangsha 410081China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China

We study the chiral bound states in a coupled-resonator array with staggered hopping strengths,which interacts with a two-level small atom through a single coupling point or two adjacent ones.In addition to the two typical bound states found above and below the energy bands,this system presents an extraordinary chiral bound state located within the energy gap.We use the chirality to quantify the breaking of the mirror symmetry.We find that the chirality value undergoes continuous changes by tuning the coupling strengths.The preferred direction of the chirality is controlled not only by the competition between the intracell and the intercell hoppings in the coupled-resonator array,but also by the coherence between the two coupling points.In the case with one coupling point,the chirality values varies monotonously with difference between the intracell hopping and the intercell hoppings.While in the case with two coupling points,due to the coherence between the two coupling points the perfect chiral states can be obtained.

关键词： bound states two-level small atom coupled-resonator array chirality

Coordinate-wise monotonic transformations enable privacy-preserving age estimation with 3D face point cloud

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Science China(Life Sciences) 2024年第7期67卷 1489-1501页

作者： Xinyu Yang Runhan Li Xindi Yang Yong Zhou Yi Liu Jing-Dong J.Han School of Life Sciences Peking UniversityBeijing 100871China Peking-Tsinghua center for Life Sciences Academy for Advanced Interdisciplinary StudiesCenter for Quantitative Biology(CQB)Peking UniversityBeijing 100871China Beijing Key Lab of Traffic Data Analysis and Mining School of Computer and Information TechnologyBeijing Jiaotong UniversityBeijing 100044China Clinical Research Institute Shanghai General HospitalShanghai Jiao Tong University School of MedicineShanghai 200025China

The human face is a valuable biomarker of aging,but the collection and use of its image raise significant privacy concerns.Here we present an approach for facial data masking that preserves age-related features using coordinate-wise monotonic transformations.We first develop a deep learning model that estimates age directly from non-registered face point clouds with high accuracy and generalizability.We show that the model learns a highly indistinguishable mapping using faces treated with coordinate-wise monotonic transformations,indicating that the relative positioning of facial information is a low-level biomarker of facial aging.Through visual perception tests and computational3D face verification experiments,we demonstrate that transformed faces are significantly more difficult to perceive for human but not for machines,except when only the face shape information is accessible.Our study leads to a facial data protection guideline that has the potential to broaden public access to face datasets with minimized privacy risks.

关键词： face point cloud age estimation face verification privacy coordinate-wise monotonic transformation

Lithium polysulfide solvation and speciation in the aprotic lithium-sulfur batteries

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Particuology 2024年第6期89卷 238-245页

作者： Jinhao Zhang Qingshan Fu Peng Li Ruibo Linghu Xiaozhong Fan Haibin Lin Juncao Bian Songbai Han Gengzhi Sun Long Kong Frontiers Science center for Flexible Electronics and Xi’an Institute of Flexible Electronics Northwestern Polytechnical UniversityXi’an710129China China Automotive Innovation Corporation Nanjing211100China Academy for Advanced interdisciplinary studies Southern University of Science and TechnologyShenzhen518055China Institute of Advanced Materials Nanjing Tech UniversityNanjing211816China

Fingerprinting sulfur speciation in aprotic electrolytes is a key to understand fundamental chemistry and design well-performing lithium–sulfur(Li–S)batteries.Lithium polysulfide(LiPS)dissolution and deposition in ether-based electrolytes during redox reactions have been probed and established by spectroscopy and microscopy.However,detailed LiPS structure and solvation properties influenced by conventional and newly developed electrolytes remain elusive,which exert fundamental challenges and practical difficulties in decoupling battery performance from electrolyte volume.This perspective aims to provide timely information to uncover underlying mechanisms that rein in sulfur speciation by considering the charge density of LiPSs and the coordination strength of solvents/salts.The discussion starts with unlocking the baseline electrolyte formulation to investigate its role in LiPS formation and compatibility.After that,the term coordination strength is used instead of donor number and dielectric constant to describe interactions between solvents and LiPSs and to reveal LiPS structure evolution.This work is expected to encourage the discovery of new electrolyte working mechanisms to develop energy-dense and power-intensive Li–S batteries.

关键词： Sulfur speciation Redox kinetics Coordination strength Solvation chemistry Lithium-sulfur batteries

Mechanism of action, benefits, and research gap in fermented soybean meal utilization as a high-quality protein source for livestock and poultry

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Animal Nutrition 2024年第1期16卷 130-146页

作者： Modinat T.Lambo Haokai Ma Haosheng Zhang Peng Song Hongxiang Mao Guowen Cui Baisheng Dai Yang Li Yonggen Zhang College of Animal Science and Technology Northeast Agricultural University Wilmar (Shanghai) biotechnology Research and Development center Co. Ltd College of Electrical Engineering and Information Northeast Agricultural University

Animal nutritionists have incessantly worked towards providing livestock with high-quality plant protein feed resources.Soybean meal (SBM) has been an essential and predominantly adopted vegetable protein source in livestock feeding for a long time;however,several SBM antinutrients could potentially impair the animal's performance and growth,limiting its use.Several processing methods have been employed to remove SBM antinutrients,including fermentation with fungal or bacterial microorganisms.According to the literature,fermentation,a traditional food processing method,could improve SBM's nutritional and functional properties,making it more suitable and beneficial to livestock.The current interest in health-promoting functional feed,which can enhance the growth of animals,improve their immune system,and promote physiological benefits more than conventional feed,coupled with the ban on the use of antimicrobial growth promoters,has caused a renewed interest in the use of fermented SBM (FSBM) in livestock diets.This review details the mechanism of SBM fermentation and its impacts on animal health and discusses the recent trend in the application and emerging advantages to livestock while shedding light on the research gap that needs to be critically addressed in future studies.FSBM appears to be a multifunctional high-quality plant protein source for animals.Besides removing soybean antinutrients,beneficial bioactive peptides and digestive enzymes are produced during fermentation,providing probiotics,antioxidants,and immunomodulatory effects.Critical aspects regarding FSBM feeding to animals remain uncharted,such as the duration of fermentation,the influence of feeding on digestive tissue development,choice of microbial strain,and possible environmental impact.

关键词： Soybean meal Protein feed Fermentation Microorganism Livestock