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Silk damping in scalar-induced gravitational waves:a novel probe for new physics

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Science china(Physics,Mechanics & Astronomy) 2025年第1期68卷 75-81页

作者： Yan-Heng Yu Sai Wang Theoretical Physics Division Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China School of Physics University of Chinese Academy of SciencesBeijing 100049China

Silk damping is well known in the study of cosmic microwave background(CMB)and accounts for suppression of the angular power spectrum of CMB on large angular *** this article,we study the effect of Silk damping on the scalar-induced gravitational waves(SIGWs).Resulting from the dissipation of cosmic fluid,the Silk damping notably suppresses the energy-density spectrum of SIGWs on scales comparable to a diffusion scale at the decoupling time of weakly-interacting *** effect offers a novel observable for probing the underlying particle interaction,especially for those mediated by heavy gauge bosons beyond the standard model of *** anticipate that pulsar timing arrays are sensitive to gauge bosons with mass∼10^(3)-10^(4)GeV,while space-and ground-based interferometers to those with mass∼10^(7)-10^(12)GeV,leading to essential comple-ments to on-going and future experiments of high-energy physics.

关键词： scalar-induced gravitational waves Silk damping new physics

Interfacial electron rearrangement of 3D Fe_(3)O_(4)/h-YFeO_(3)composites for efficient electromagnetic wave absorption

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International Journal of Minerals,Metallurgy and Materials 2025年第3期32卷 609-618页

作者： Yi Sui Yingde Zhang Guang Liu Lei Ji Junyu Yue Chen Wu Mi Yan School of Materials Science and Engineering Zhejiang UniversityHangzhou 310027China State Key Laboratory of Baiyunobo Rare Earth Resource researches and Comprehensive Utilization Baotou Research Institute of Rare EarthsBaotou 014030China Key Laboratory of Rare Earths Chinese Academy of SciencesGanzhou 341119China Shanxi-Zheda Institute of advanced Materials and Chemical Engineering Taiyuan 030032China

Interface modulation is an important pathway for highly efficient electromagnetic wave ***,tailored interfaces between Fe_(3)O_(4)particles and the hexagonal-YFeO_(3)(h-YFeO_(3))framework were constructed via facile *** resulting interfa-cial electron rearrangement at the heterojunction led to enhanced dielectric and magnetic loss *** results and density function theory(DFT)simulations demonstrate a transition in electrical properties from a half-metallic monophase to metallic Fe_(3)O_(4)/h-YFeO_(3)composites,emphasizing the advantages of the formed *** transformation of electron behavior is also accompan-ied by a redistribution of electrons at the Fe_(3)O_(4)/h-YFeO_(3)heterojunction,leading to the accumulation of localized electrons around the Y-O-Fe band bridge,consequently enhancing the polarization.A minimum reflection loss of-34.0 dB can be achieved at 12.0 GHz and 2.0 mm thickness with an effective bandwidth of 3.3 GHz due to the abundant interfaces,enhanced polarization,and rational ***,the synergistic effects endow the Fe_(3)O_(4)/h-YFeO_(3)composites with high performance and tunable functional properties for efficient electromagnetic absorption.

关键词： self-assembling heterojunction electron rearrangement interface modulation electromagnetic wave absorption

The Impact of Different Effective Models for Star Formation on the Properties of Simulated Milky Way-sized Galaxies

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research in Astronomy and Astrophysics 2025年第1期25卷 194-210页

作者： Yiheng Wu Volker Springel Shanghai Astronomical Observatory Chinese Academy of Sciences University of Chinese Academy of Sciences Max-Planck-Institut für Astrophysik

Hydrodynamical cosmological simulations of galaxy formation such as Illustris TNG or Auriga have shown considerable success in approximately matching many galaxy properties,but their treatment of the star-forming interstellar medium (ISM) has relied on heuristic sub-grid ***,recent high-resolution simulations of the ISM that directly resolve the regulation of star formation suggest different mean relations for the dependences of pressure and star formation rate on the average gas *** this study,we adopt such a modern,physically grounded parameterization inspired by the TIGRESS small-scale *** dub this model TEQS and use it for a detailed comparative analysis of the formation and evolution of a Milky Way-sized galaxy when compared with the widely used TNG *** employing high-resolution simulations in tall box setups,we first investigate the structural differences expected for these two models when applied to different self-gravitating gas surface *** results indicate that TEQS produces considerably thinner gaseous layers and can be expected to form stellar distributions with smaller scale-height than TNG,especially at higher surface *** test whether this induces systematic structural differences in cosmological galaxy formation simulations,we carry out zoom-in simulations of 12 galaxies taken from the set of Milky Way-sized galaxies that have been studied in the Auriga *** results for these galaxies shows that disk galaxies formed with the TEQS model have on average very similar stellar mass but are more concentrated in their central regions and exhibit smaller stellar radii compared to those formed with the TNG *** differences in the scale-heights of the formed stellar disks are only marginal,however,suggesting that other factors for setting the thickness of the disk are more important than the applied ISM equation-of-state ***,the predicted galaxy structure is quite similar for TNG and

关键词： Galaxy: evolution Galaxy: formation methods: numerical

Constraints on holographic QCD phase transitions from PTA observations

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Science china(Physics,Mechanics & Astronomy) 2025年第1期68卷 67-74页

作者： Song He Li Li Sai Wang Shao-Jiang Wang Center for Theoretical Physics and College of Physics Jilin UniversityChangchun 130012China School of Physical Science and Technology Ningbo UniversityNingbo 315211China CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of Sciences(UCAS)Hangzhou 310024China Theoretical Physics Division Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China School of Physical Sciences University of Chinese Academy of Sciences(UCAS)Beijing 100049China Max Planck Institute for Gravitational Physics(Albert Einstein Institute) Am Muhlenberg 1Golm 14476Germany

The underlying physics of QCD phase transition in the early Universe remains largely unknown due to its strong-coupling nature during the quark-gluon plasma/hadron gas transition,yet a holographic model has been proposed to quantitatively fit the lattice QCD data while with its duration of the first-order phase transition(FoPT)left *** specific baryon chemical poten-tial,the first-order QCD phase transition agrees with the observational constraint of baryon ***,therefore,provides a scenario for phase transition gravitational waves(GWs)within the standard model of particle *** these background GWs could contribute dominantly to the recently claimed common-spectrum red noise from pulsar timing array(PTA)observations,the duration of this FoPT can be well constrained,and the associated primordial black holes are still allowed by current observations.

关键词： pulsar timing array QCD phase transition gravitational waves primordial black holes

Development of Gravity Theories in the View of TRAPPIST-1e

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research in Astronomy and Astrophysics 2025年第1期25卷 143-161页

作者： Nan Wang Lu-Yao Lu Hui-Gen Liu An-Dong Chen Tiger Lu Ao-Ran Cui Jun-Kai Wang Marine Science and Technology College Zhejiang Ocean University Key Laboratory of Modern Astronomy and Astrophysics Ministry of Education Zhoushan Astronomical Society School of Astronomy and space Science Nanjing University Department of Astronomy Yale University Kuang Yaming Honors School Nanjing University School of Physics Nanjing University

Contrary to the solar system, most exoplanet systems detected hitherto are close-in and compact. One typical system is TRAPPIST-1, which has seven nearly co-planar terrestrial planets all within the orbit of Mercury,including three in the habitable zone. To evaluate the differences in developing sophisticated gravity theories from the solar system, we use N-body integrations to simulate ephemeris and reproduce some important astronomy phenomena observed on the potentially habitable planet TRAPPIST-1e. Retrograde motions of other planets last1–2 orders of magnitude shorter than in the solar system, but occur much more frequently. Transit events of all inner planets can be observed steadily. Except for Kepler's first law, which is hard to notice for low eccentricities of planets, the other two laws can then be precisely verified in 102days, because the areas swept by planets vary by?0.01% and the observed semimajor axes and periods result in constants with theoretical and observation accuracies both ?2%. However, the mean motion correlation implies that the Great Inequality is not always apparent between one pair of planets like Jupiter and Saturn. Furthermore, general relativity can hardly be discovered because it gives rise to perihelion precession of inner planets only ～0.1% of gravity precession, dozens of times smaller than Mercury. Our results support the possibility of developing part of gravity theories by potential exo-civilizations in compact systems like TRAPPIST-1.

关键词： ephemerides extraterrestrial intelligence gravitation planets and satellites: terrestrial planets

Einstein Probe discovery of EP240408a:A peculiar X-ray transient with an intermediate timescale

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Science china(Physics,Mechanics & Astronomy) 2025年第1期68卷 218-236页

作者： Wenda Zhang Weimin Yuan Zhixing Ling Yong Chen Nanda Rea Arne Rau Zhiming Cai Huaqing Cheng Francesco Coti Zelati Lixin Dai Jingwei Hu Shumei Jia Chichuan Jin Dongyue Li Paul O’Brien Rongfeng Shen Xinwen Shu Shengli Sun Xiaojin Sun Xiaofeng Wang Lei Yang Bing Zhang Chen Zhang Shuang-Nan Zhang Yonghe Zhang Jie An David Buckley Alexis Coleiro Bertrand Cordier Liming Dou Rob Eyles-Ferris Zhou Fan Hua Feng Shaoyu Fu Johan P.U.Fynbo Lluis Galbany Saurabh W.Jha Shuaiqing Jiang Albert Kong Erik Kuulkers Weihua Lei Wenxiong Li Bifang Liu Mingjun Liu Xing Liu Yuan Liu Zhu Liu Chandreyee Maitra Alessio Marino Itumeleng Monageng Kirpal Nandra Jeremy Sanders Roberto Soria Lian Tao Junfeng Wang Song Wang Tinggui Wang Zhongxiang Wang Qingwen Wu Xuefeng Wu Dong Xu Yanjun Xu Suijian Xue Yongquan Xue Zijian Zhang Zipei Zhu Hu Zou Congying Bao Fansheng Chen Houlei Chen Tianxiang Chen Wei Chen Yehai Chen Yifan Chen Chenzhou Cui Weiwei Cui Yanfeng Dai Dongwei Fan Ju Guan Dawei Han Dongjie Hou Haibo Hu Maohai Huang Jia Huo Zhenqing Jia Bowen Jiang Ge Jin Chengkui Li Junfei Li Longhui Li Maoshun Li Wei Li Zhengda Li Tianying Lian Congzhan Liu Heyang Liu Huaqiu Liu Fangjun Lu Laidan Luo Jia Ma Xuan Mao Haiwu Pan Xin Pan Liming Song Hui Sun Yunyin Tan Qingjun Tang Yihan Tao Hao Wang Juan Wang Lei Wang Wenxin Wang Yilong Wang Yusa Wang Qinyu Wu Haitao Xu Jingjing Xu Xinpeng Xu Yunfei Xu Zhao Xu Changbin Xue Yulong Xue Ailiang Yan Haonan Yang Xiongtao Yang Yanji Yang Juan Zhang Mo Zhang Wenjie Zhang Zhen Zhang Zhen Zhang Ziliang Zhang Donghua Zhao Haisheng Zhao Xiaofan Zhao Zijian Zhao Hongyan Zhou Yilin Zhou Yuxuan Zhu Zhencai Zhu National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China School of Astronomy and space Sciences University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China Institute of space Sciences(ICE) CSICBarcelona E-08193Spain Institut d’Estudis Espacials de Catalunya(IEEC) Barcelona E-08034Spain Max Planck Institute for Extraterrestrial Physics Garching 85748Germany Innovation Academy for Microsatellites Chinese Academy of SciencesShanghai 201210China Department of Physics University of Hong KongHong Kong 999077China School of Physics and Astronomy University of LeicesterLeicester LE17RHUK School of Physics and Astronomy Sun Yat-sen UniversityZhuhai 519082China Department of Physics Anhui Normal UniversityWuhu 241002China Shanghai Institute of Technical Physics Chinese Academy of SciencesShanghai 200083China Physics Department Tsinghua UniversityBeijing 100084China Nevada Center for Astrophysics University of Nevada Las VegasLas Vegas NV 89154USA Department of Physics and Astronomy University of Nevada Las VegasLas Vegas NV 89154USA South African Astronomical Observatory Cape Town 7935South Africa Department of Astronomy University of Cape TownRondebosch 7701South Africa Department of Physics University of the Free StateBloemfontein 9300South Africa Universit´e Paris Cit´e CNRSAstroparticule et CosmologieParis F-75013France Universit´e Paris Cit´e CEA Paris-SaclayIRFU/DAp-AIMGif-sur-Yvette 91191France Department of Astronomy Guangzhou UniversityGuangzhou 510006China Cosmic Dawn Center(DAWN) Copenhagen 2200Denmark Niels Bohr Institute University of CopenhagenCopenhagen 2200Denmark Department of Physics and Astronomy Rutgersthe State University of New JerseyPiscataway NJ 08854-8019USA Institute for Cosmic Ray research The University of TokyoKashiwa City 277-8582Japan ESA/ESTEC Noordwijk 2201 AZThe Netherlands Department of Astronom

We report the discovery of a peculiar X-ray transient,EP240408a,by Einstein Probe(EP)and follow-up studies made with EP,Swift,NICER,GROND,ATCA and other ground-based multiwavelength *** new transient was first detected with Wide-field X-ray Telescope(WXT)on board EP on April 8th,2024,manifested in an intense yet brief X-ray flare lasting for 12 *** flare reached a peak flux of 3:9×10^(−9) erg cm^(−2) s^(−1) in 0.5-4 keV,∼300 times brighter than the underlying X-ray emission detected throughout the *** and more precise follow-up observations by EP/FXT,Swift and NICER confirmed the finding of this new *** X-ray spectrum is non-thermal in 0.5-10 keV,with a power-law photon index varying within *** X-ray light curve shows a plateau lasting for∼4 d,followed by a steep decay till becoming undetectable∼10 d after the initial *** on its temporal property and constraints from previous EP observations,an unusual timescale in the range of 7-23 d is found for EP240408a,which is intermediate between the commonly found fast and long-term *** counterparts have been found in optical and near-infrared,with the earliest observation at 17 h after the initial X-ray detection,suggestive of intrinsically weak emission in these *** demonstrate that the remarkable properties of EP240408a are inconsistent with any of the transient types known so far,by comparison with,in particular,jetted tidal disruption events,gamma-ray bursts,X-ray binaries and fast blue optical *** nature of EP240408a thus remains an *** suggest that EP240408a may represent a new type of transients with intermediate timescales of the order of∼10 *** detection and follow-ups of more of such objects are essential for revealing their origin.

关键词： X-ray transients Einstein Probe

Ultra-stable Co-based metallic glassy microwires for highly sensitive giant-magnetoimpedance sensors

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Science china(Physics,Mechanics & Astronomy) 2025年第04期Mechanics & Astronomy) .卷 156-164页

作者： Yuyang Qian Chaoqun Pei Haibo Ke Xintao Wei Dengke Wang Yandong Jia Baoan Sun Gang Wang Weihua Wang Institute of Materials School of Materials Science and Engineering Shanghai University Songshan Lake Materials Laboratory Institute of Physics Chinese Academy of Sciences

The development and deployment of giant magnetoimpedance(GMI) sensors have been significantly hampered by their limited sensitivity to weak magnetic fields and pronounced thermal drift phenomena, both of which are intricately linked to the microstructural properties of the sensor core material, typically composed of metallic glass microwires(MGMWs). Herein, we successfully fabricated an ultra-stable Co-based MGMW with a high GMI effect through a novel multi-step stress-Joule coupled annealing(MS-JCA) technique. The Co-based MGMW showcases a significantly improved GMI effect with an unprecedented impedance change rate of 939%, coupled with an enhanced magnetic field sensitivity of 734%/Oe. In addition,the MS-JCA process ensures the GMI sensor retains exceptional stability during thermal drift measurements over a span of20 h, characterized by a minimal signal fluctuation ratio of merely 0.59%. Notably, the ultra-stability of the GMI sensor arises from the ultra-stable energy state of the MGMWs following MS-JCA. Our findings offer a compelling strategy for significantly enhancing both the performance and stability of GMI sensors, thereby establishing a solid technical foundation for their broader application in weak magnetic detection.

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Syndrome Differentiation of Chinese Medicine in Mars 500 Long-Term Closed Environment

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Chinese Journal of Integrative Medicine 2020年第6期26卷 428-433页

作者： SHI Hong-zhi FAN Quan-chun BAI Gui-e GAO Jian-yi LIU Jun-lian MI Tao ZHAO Shuang LIU Yu GUO Li-guo XU Dong LI Yong-zhi CHEN Kai-xian State Key Laboratory of space Medicine Fundam entals and Application China Astronaut Research and Training CenterBeijing(100094)China Shanghai University of Traditional Chinese Medicine Shanghai(201203)China

Objective:To summarize and elucidate the characteristics and evolvement of Chinese medicine(CM)patterns reflecting the physical and mental conditions of participants in the Mars 500 long-term closed ***:The DS01-T Digital TCM Four-Diagnostic Instrument and CM Inquiring Diagnostic Questionnaire were used to collect information from 6 participants in the Mars 500 International Joint research Project,through diagnostic methods of observation,palpation and inquiry according to CM *** the 520 days of the experiment,data collection was performed 37 times;a total of over 400 digital images of tongues and facial complexion and over 20,000 data were *** data were then analyzed by a team of experts in CM,statistics,and data ***:The CM pattern evolvement of participants in the long-term closed environment followed some common *** deficiency was the main CM pattern observed,with individual features depending on constitutional differences[manifested in varying degrees of accompanying patterns of Gan(Liver)qi stagnation,Pi(Spleen)deficiency,dampness encumbering,or yin deficiency].Conclusion:The research has verified the effectiveness of CM syndrome differentiation based on the four diagnostic methods,which should serve as a solid foundation for observation,monitoring,and intervention in regard to the health conditions of astronauts in long-term space flights in the future.

关键词： Mars 500 long-term closed environment health condition syndrome differentiation Chinese medicine

Evaluation of the Health Status of Six Volunteers from the Mars 500 Project Using Pulse Analysis

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Chinese Journal of Integrative Medicine 2017年第8期23卷 574-580页

作者： SHI Hong-zhi FAN Quan-chun GAO Jian-yi LIU Jun-lian BAI Gui-e MI Tao ZHAO Shuang LIU Yu XU Dong GUO Zhi-feng LI Yong-zhi State Key Laboratory of space Medicine Fundamentals and Application China Astronaut Research and Training Center Beijing 100094 China

Objective：To comprehensively evaluate the health status of 6 volunteers from the Mars 500Project through analyzing their pulse graphs and determining the changes in cardiovascular function,degree of fatigue and autonomic nervous ***：Six volunteers were recruited;all were male aged 26–38years（average 31.83±4.96 years）.Characteristic parameters reflecting the status of cardiovascular functions were extracted,which included left ventricular contraction,vascular elasticity and peripheral *** degree of fatigue was determined depending on the difference between the calendar age and biological age,which was calculated through the analysis of blood pressure value and characteristic *** on the values of pulse height variation and pulse time variation on a 30-s pulse graph,autonomic nervous function was *** parameters examined were marked on an equilateral polygon to form an irregular polygon of the actual figure,then health status was evaluated based on the coverage area of the actual ***：The results demonstrated：（1）volunteers developed weakened pulse power,increased vascular tension and peripheral resistance,and slight decreased ventricular systolic function;（2）the degree of fatigue was basically mild or moderate;and（3）autonomic nervous function was excited but generally ***：These volunteers were in the state of *** to Chinese medicine theories,such symptoms are mainly caused by the weakening of healthy qi,Gan（Liver）failing in free coursing,and disharmony between Gan and Wei（Stomach）,which manifests as a weak and string-like pulse.

关键词： pulse graph cardiovascular function fatigue autonomic nervous function sub-health