Science China Physics, Mechanics & Astronomy最新文献

{"title":"Space-weathering induced nanoporous nanophase iron in ilmenite on the lunar far side","authors":"Yajing Song,&nbsp;Jiawei Zou,&nbsp;Yingjie Zhou,&nbsp;Zitong Wang,&nbsp;Jiaxuan Tang,&nbsp;Yujie Chen,&nbsp;Yan Fang,&nbsp;Yangjian Lin,&nbsp;Yang Li,&nbsp;Xiaolong Chen,&nbsp;Lin Gu,&nbsp;Qian Yu","doi":"10.1007/s11433-026-3043-7","DOIUrl":"10.1007/s11433-026-3043-7","url":null,"abstract":"<div><p>The structure and composition of the lunar surface are heavily influenced by redox reactions driven by space weathering. Investigating these effects provides critical insights into the evolution of the lunar environment and identifies essential resources for future human exploration. However, this issue remains unexplored on the far side of the Moon due to technological constraints in lunar exploration. Here, we investigated the effect of space weathering on ilmenite retrieved by Chang’e-6 from the far side of the Moon for the first time. Compared with previous studies on lunar weathering rims, the results highlight several distinct features: (1) the relatively high area fraction of nanophase iron within the weathering rims; (2) formation of a pronounced nanoporous nanophase iron, accompanied by the weak signal of hydrogen and notable loss of oxygen (approximately 7 at%); and (3) the predominant presence of Ti²⁺. These observations collectively point to an extensive reduction reaction. Meanwhile, a nonuniform distribution of hydrogen-related species was detected in three dimensions, extending to depths exceeding one micron. Our results underscore the critical role of chemical reactions in modifying the composition and morphology of the lunar surface on the Moon’s far side, providing compelling evidence of the diversity in the Moon’s geologic evolution on the far side.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"69 10","pages":""},"PeriodicalIF":7.2,"publicationDate":"2026-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11433-026-3043-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148928025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stochasticity vs. chaos: A common methodology to study astrophysical transients and the mystery of fast radio bursts","authors":"Bing Zhang","doi":"10.1007/s11433-026-3039-3","DOIUrl":"10.1007/s11433-026-3039-3","url":null,"abstract":"","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"69 10","pages":""},"PeriodicalIF":7.2,"publicationDate":"2026-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148928027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cosmological preference for a positive neutrino mass at 2.7σ: A joint analysis of DESI DR2, DESY5, and DESY1 data","authors":"Guo-Hong Du,&nbsp;Tian-Nuo Li,&nbsp;Peng-Ju Wu,&nbsp;Jing-Fei Zhang,&nbsp;Xin Zhang","doi":"10.1007/s11433-026-3051-4","DOIUrl":"10.1007/s11433-026-3051-4","url":null,"abstract":"<div><p>Neutrinos and dark energy (DE) have entered a new era of investigation, as the latest DESI baryon acoustic oscillation measurements tighten the constraints on the neutrino mass and suggest that DE may be dynamical rather than a cosmological constant. In this work, we obtain a high-confidence measurement of the neutrino mass within a dynamical DE framework. A joint analysis of DESI DR2, cosmic microwave background, DESY5 supernova, and DESY1 weak lensing data yields a total neutrino mass of <span>(sum m_{nu} = 0.098^{+0.016}_{-0.037}, text{eV})</span>, indicating a measurement for a non-zero, positive neutrino mass at the 2.7<i>σ</i> level within the <i>w</i>₀<i>w</i>_<i>a</i>CDM framework. This high-confidence measurement is driven mainly by these factors: (i) the DESI’s preference for a dynamical DE with its equation of state evolving from <i>w</i> &lt; −1 at early times to <i>w</i> &gt; −1 at late times, thus leading to a larger neutrino mass; (ii) treating <i>N</i>_eff as a free parameter together with the inclusion of weak lensing data, which likewise allows for an increased neutrino mass. In the future, even higher-confidence measurements of neutrino mass are expected with stronger preferences for dynamical DE in light of more complete DESI data releases.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"69 10","pages":""},"PeriodicalIF":7.2,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148927910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Submonolayer quantum dot light-emitting devices enable efficient sub-bandgap-voltage emission","authors":"Weibin Lin,&nbsp;Yiqi You,&nbsp;Haiyan Lin,&nbsp;Kuibao Yu,&nbsp;Zhihan Lin,&nbsp;Yongshen Yu,&nbsp;Fushan Li,&nbsp;Hailong Hu","doi":"10.1007/s11433-026-3040-7","DOIUrl":"10.1007/s11433-026-3040-7","url":null,"abstract":"<div><p>Quantum dot light-emitting diodes (QLEDs) with high external quantum efficiency (EQE) are attractive candidates for wearable integrated displays. However, the pursuit of high power efficiency—especially high EQE at low operating voltages-has long been hampered by interlayer charge injection barriers and inefficient intralayer charge transport. Here, we report a rational strategy to construct a submonolayer (sub-ML) quantum dot (QD) emissive layer (EML) using Langmuir-Blodgett assembly. We fabricate a closely packed monolayer of QD/NaYF₄ hybrid nanoparticles (NPs), wherein each QD is precisely positioned to establish direct contact with both the electron transport layer (ETL) and hole transport layer (HTL), thus eliminating vertical charge transport between adjacent QDs. Critically, partial replacement of QDs with insulating NaYF₄ NPs introduces localized electrostatic fields via embedded equivalent nanocapacitors, which substantially enhances the hole injection level. The sub-ML QLEDs realize efficient sub-bandgap-voltage emission, delivering a practical luminance of 585 cd m⁻² at a low driving voltage of 1.8 V. These devices exhibit a maximum external power efficiency of 23.7% and a power efficiency of 40.37 lm W⁻¹, representing 56% and 87% improvements, respectively, over optimized monolayer QLEDs. Our approach offers a viable solution to the long-standing efficiency-voltage trade-off, paving the way for the development of low-power, high-performance QLEDs.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"69 10","pages":""},"PeriodicalIF":7.2,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148927894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tunable altermagnetic quantum spin Hall and ferrimagnetic quantum anomalous Hall effects in few-layer FeNbX2 (X=Se, Te)","authors":"M. U. Muzaffar,&nbsp;Xiaoyu Zhu,&nbsp;Guohua Cao,&nbsp;Wei Qin,&nbsp;Ping Cui,&nbsp;Shun-Qing Shen,&nbsp;Zhenyu Zhang","doi":"10.1007/s11433-026-3037-4","DOIUrl":"10.1007/s11433-026-3037-4","url":null,"abstract":"<div><p>The interplay of spin, orbital, and spin-orbit coupling often gives rise to exotic phases of matter, including notably the quantum spin Hall (QSH) and quantum anomalous Hall (QAH) states. Achieving controllable switching between these phases in a single material platform holds great promise for future device applications. Here we predict FeNbX₂ (X=Se, Te) as an appealing class of layered materials that can harbor thickness-dependent QSH and QAH states at elevated temperatures, with intriguing ferrimagnetic or altermagnetic characteristics. We first show that in the monolayer regime, both systems exhibit ferrimagnetism and behave as QAH insulators at room temperature. In contrast, the two systems behave distinctly differently in the multilayer regime. For FeNbSe₂, the interlayer coupling is antiferromagnetic, and the materials exhibit layer-dependent topological properties, with the odd layers hosting ferrimagnetic QAH states of a constant Chern number <i>C</i>=2, while even layers hosting altermagnetic QSH states with a thickness-dependent spin Chern number <i>C</i>_s of ∣<i>C</i>_s∣=2 or higher. For FeNbTe₂, the interlayer coupling is ferromagnetic, and the materials always exhibit QAH states with a thickness-dependent Chern number <i>C</i>⩾2. These findings offer unique materials platforms for achieving convertible QAH and QSH states for future dissipationless quantum devices.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"69 10","pages":""},"PeriodicalIF":7.2,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148927917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MeV gamma-ray lines from radioactive nuclei in magnetar giant flares","authors":"Wu-Zimo Qiumu,&nbsp;Meng-Hua Chen,&nbsp;Qiu-Hong Chen,&nbsp;Fei Xie,&nbsp;Hou-Jun Lü,&nbsp;Xiang-Gao Wang,&nbsp;En-Wei Liang","doi":"10.1007/s11433-026-3045-7","DOIUrl":"10.1007/s11433-026-3045-7","url":null,"abstract":"<div><p>The rapid neutron-capture process (<i>r</i>-process) is widely regarded as the dominant mechanism responsible for the synthesis of heavy elements in the universe, yet its astrophysical sites remain an open question. Recent studies suggest that the high-entropy, rapidly expanding baryonic material ejected by magnetar giant flares may provide favorable conditions for <i>r</i>-process nucleosynthesis, while the late-time gamma-ray emission observed from the magnetar SGR 1806-20 offers direct observational support for this scenario. In this work, we perform nuclear reaction network simulations to investigate the nucleosynthesis yields of magnetar giant flares and to characterize the associated nuclear gamma-ray line emission arising from the radioactive decay of heavy nuclei. The nuclei synthesized in magnetar giant flares are found to be mainly distributed near the first and second r-process abundance peaks. Owing to this nuclide composition, the gamma-ray opacity is found to be strongly energy-dependent, with the opacity in the keV band exceeding that in the MeV band by approximately three orders of magnitude. The nuclear gamma-ray emission is dominated by MeV photons at early times (<i>t</i> ≲ 10³ s) and gradually extends toward the sub-MeV and keV bands as time progresses, thereby offering a diagnostic of heavy element enrichment in the ejecta. The gamma-ray spectrum exhibits a peak near ∼ 1 MeV with major contributions from ⁸⁸Kr and ⁹²Sr, whose radioactive decays produce several bright gamma-ray lines with fluxes exceeding ∼ 10⁻⁸ erg cm⁻² s⁻¹, making them the most promising lines for detection by MeV gamma-ray detectors. Because magnetar giant flares occur in the Galaxy at a rate roughly three orders of magnitude higher than neutron star mergers and their nuclear gamma-ray lines are accessible to current MeV instruments, they offer new and valuable science opportunities for MeV gamma-ray astronomy.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"69 10","pages":""},"PeriodicalIF":7.2,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148927898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Probing nuclear deformation with differential radial flow in heavy-ion collisions","authors":"Jie Zhu,&nbsp;Xiang-Yu Wu,&nbsp;Guang-You Qin","doi":"10.1007/s11433-026-3029-1","DOIUrl":"10.1007/s11433-026-3029-1","url":null,"abstract":"<div><p>In relativistic heavy-ion collisions, the radial flow of the fireball, usually characterized by transverse momentum spectra of final-state particles, encodes essential information about the hot and dense nuclear matter created in the collisions. However, the response of radial flow, including its <i>p</i>_<i>T</i>-differential structure <i>v</i>₀(<i>p</i>_<i>T</i>) and longitudinal fluctuations <i>v</i>₀(<i>η</i>), to intrinsic nuclear deformation remains unexplored. Using realistic (3 + 1)-dimensional viscous hydrodynamic calculations with T_RENTo-3D initial conditions, we investigate how nuclear deformation affects the differential radial flow. We observe a clear, positive correlation between quadrupole deformation <i>β</i>₂ and radial flow: the magnitudes of both <i>v</i>₀ and <i>v</i>₀(<i>p</i>_<i>T</i>) are enhanced in central collisions when <i>β</i>₂ is increased. In contrast, the scaled radial flow <i>v</i>₀(<i>p</i>_<i>T</i>)/<i>v</i>₀ remains nearly independent of <i>β</i>₂, and the Pearson coefficient <i>ρ</i>(<i>n</i>(<i>p</i>_<i>T</i>), [<i>p</i>_<i>T</i>]) exhibits a universal step-like behavior across all collision systems and centralities. Further analysis of longitudinal decorrelation of radial flow reveals a rich structure: in central collisions, large <i>β</i>₂ tends to suppress the decorrelation, whereas hexadecapole deformation <i>β</i>₄ tends to enhance it. This decorrelation effect increases toward peripheral collisions. Our results suggest that radial flow fluctuation observables, especially their longitudinal dependence, may provide useful complementary information on nuclear deformation in high-energy nucleus-nucleus collisions.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"69 10","pages":""},"PeriodicalIF":7.2,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148837570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatially indirect exciton condensation in two-dimensional strongly correlated semimetals","authors":"Yao Zeng,&nbsp;Shi-Cong Mo,&nbsp;Xiang Chen,&nbsp;Wéi Wú","doi":"10.1007/s11433-026-3047-7","DOIUrl":"10.1007/s11433-026-3047-7","url":null,"abstract":"<div><p>Identifying materials hosting an excitonic insulator ground state has been one of the major pursuits in condensed matter physics in recent years. Promising candidates in transition metal chalcogenide compounds (TMCs), including 1<i>T</i>-TiSe₂, Ta₂Pd₃Te₅, and Ta₂NiSe₅, share a crucial common characteristic: their low-energy physics is governed by electrons in <i>d</i>-orbitals subject to strong on-site Coulomb interactions. In this work, we investigate spatially indirect exciton condensation in two-dimensional semimetals on a triangular lattice. Using a combination of dynamical mean-field theory and the determinant quantum Monte Carlo method, we study two- and three-orbital Hubbard models incorporating strong on-site (<i>U</i>) and inter-orbital interactions (<i>V</i>). Our results demonstrate that on-site Hubbard <i>U</i> can strongly suppress the condensation temperature <i>T</i>_<i>c</i>, an effect that is particularly pronounced at higher electron-hole pair densities. This behavior contrasts sharply with the case without on-site <i>U</i>, where <i>T</i>_<i>c</i> grows with pair density at fixed <i>V</i>. Moreover, we uncover competition among multiple electron-hole pairing channels in the three-orbital model, which also acts to suppress <i>T</i>_<i>c</i> of exciton condensation. An orbital-selective electron-hole pairing state is identified. These findings may help explain the large discrepancy between strong binding energy and relatively low transition temperature for indirect excitons in TMC materials, offering important insights for understanding and engineering exciton condensation in materials with strongly correlated <i>d</i>-shell electrons.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"69 10","pages":""},"PeriodicalIF":7.2,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148837571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unveiling the spectral morphological division of fast radio bursts with CHIME/FRB Catalog 2","authors":"Wan-Peng Sun,&nbsp;Yin-Long Cao,&nbsp;Yong-Kun Zhang,&nbsp;Ji-Guo Zhang,&nbsp;Xiaohui Liu,&nbsp;Yichao Li,&nbsp;Fu-Wen Zhang,&nbsp;Wan-Ting Hou,&nbsp;Jing-Fei Zhang,&nbsp;Xin Zhang","doi":"10.1007/s11433-026-3036-5","DOIUrl":"10.1007/s11433-026-3036-5","url":null,"abstract":"<div><p>Fast radio bursts (FRBs) are commonly classified into repeating and apparently nonrepeating sources, yet whether this distinction reflects intrinsically different physical populations remains uncertain. Using the Second CHIME/FRB Catalog, we apply an unsupervised machine learning framework combining uniform manifold approximation and projection (UMAP) with density-based clustering to investigate the intrinsic structure of the FRB population in a multi-dimensional parameter space. We find that FRBs are primarily separated into two robust clusters dominated by spectral morphology. One cluster is characterized by narrowband emission and longer durations, while the other exhibits relatively broadband spectra and shorter burst timescales, confirming previous findings based on the first CHIME/FRB catalog. This classification scheme achieves a recall of 0.94 for known repeaters. Within the repeating population, we further identify a stable subclass of atypical repeaters that are broadband, shorter in duration, and more luminous, resembling nonrepeating bursts. Furthermore, broadband nonrepeaters exhibit systematically higher dispersion measures (by approximately 200 pc cm⁻³) and isotropic luminosities approximately an order of magnitude larger than those of repeating FRBs. Without invoking catastrophic progenitor scenarios, these differences are naturally explained by instrumental sensitivity limits and distance-dependent selection effects. Our results provide new statistical evidence for a physical connection between repeating and nonrepeating FRBs.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"69 10","pages":""},"PeriodicalIF":7.2,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148927914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The stochastic and chaotic behaviour of fast radio bursts, compared to quake and flare model families","authors":"Joeri van Leeuwen","doi":"10.1007/s11433-026-3053-4","DOIUrl":"10.1007/s11433-026-3053-4","url":null,"abstract":"","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"69 10","pages":""},"PeriodicalIF":7.2,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148927895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}