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Exploring hidden-charm and hidden-strange hexaquark states from lattice QCD

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Science China(physics,Mechanics & Astronomy) 2024年第1期67卷 30-37页

作者： Hang Liu Jinchen He Liuming Liu Peng Sun Wei Wang Yi-Bo Yang Qi-An Zhang INPAC Key Laboratory for Particle Astrophysics and Cosmology(MOE)Shanghai Key Laboratory for Particle Physics and CosmologySchool of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Maryland Center for Fundamental physics Department of PhysicsUniversity of MarylandCollege ParkMaryland 20742USA Institute of Modern physics Chinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China Department of physics and Institute of Theoretical physics Nanjing Normal UniversityNanjing 210023China Southern Center for Nuclear-Science Theory(SCNT) Institute of Modern PhysicsChinese Academy of SciencesHuizhou 516000China 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 StudyUCASHangzhou 310024China International Centre for Theoretical physics Asia-Pacific Beijing 100049/Hangzhou 310024China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China School of physics Beihang UniversityBeijing 102206China

Based on five different ensembles of newly generated(2+1)-flavor configurations with pion mass of approximately mπ■(140-310)MeV,we present a lattice analysis of hidden-charm and hidden-strange hexaquarks with the quark content■.The correlation matrices of two types of operators with JPC=0++,0-+,1++and 1--are simulated to extract the masses of the hexaquark candidates,which are subsequently extrapolated to the physical pion mass and continuum limit.The results indicate that ground state masses are below the■threshold and provide a characteristic signal for the experimental discovery of hexaquark candidates,which may enrich the versatile structure of multiquarks;moreover,it is an indispensable step to decipher the nonperturbative nature of the fundamental interactions of quarks and gluons.

关键词： quantum chromodynamics lattice QCD multiquark states

Light People:professor Laura Na Liu

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Light(Science & Applications) 2024年第2期13卷 184-189页

作者： Hui Wang Cun Yu Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of Sciences130033ChangchunChina

Editorial The DNA nanotechnology outlines a new chapter in biological sciences,opening a new era of scientific and technological advancements.A pioneer of DNA nanotechnology,professor Liu from the University of Stuttgart in Germany,our latest Light People,has been working at the interface,where nanophotonics meets biology and chemistry.On the path of scientific explorations.

关键词： chemistry. advancement pioneer

Probing the Gamma-Ray Emission Region of Five TeV Flat Spectrum Radio Quasars

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Research in Astronomy and Astrophysics 2024年第6期24卷 158-171页

作者： Hu-Bing Xiao Hai-Tao Cao Rui Xue Jin-Ting Cai Ge-Ge Wang Marina Manganaro Shao-Hua Zhang Zhi-Hao Ouyang Li-Ping Fu Jun-Hui Fan Shanghai Key Lab for Astrophysics Shanghai Normal University School of Information Engineering Department of physics Zhejiang Normal University College of Mathematics and physics Guangxi Minzu University Key Laboratory of Cosmology and Astrophysics (Liaoning) College of Sciences Northeastern University Department of physics University of Rijeka Center for Astrophysics Guangzhou University Key Laboratory for Astronomical Observation and Technology of Guangzhou Astronomy Science and Technology Research Laboratory of Department of Education of Guangdong Province

The location of γ-ray emission of blazars remains a contested topic, inspiring the development of numerous investigative techniques to address this issue. In this work, we analyzed Fermi γ-ray light curves in the GeV and MeV bands, employing the discrete cross-correlation function method to discern time lags between the two bands.For 4C +21.35, Ton 599, B2 1420+32, and PKS 1510-089, we identified a time lag spanning several days, while for PKS 1441+25, the time lag was not statistically found. The results imply that the soft photons necessary for inverse Compton scattering predominantly originate from the dusty torus in the first four sources, whereas for PKS1441+25, they seem to be sourced mainly from the broad-line region. Further analysis of the opacity(τγγ) and the GeV spectra study supports the conclusion that the location of the dissipation region must be beyond the BLR to avoid significant absorption. Notably, for PKS 1441+25, the emission region is also posited to lie outside yet proximate to the BLR. The parameters of describing the emission region were obtained by fitting broadband spectral energy distribution with contemporaneous observation data. Our findings suggest that for the five TeV FSRQs, during Te V flaring events, the jet appears to maintain an equilibrium between the energy density of the magnetic field and that of the particles for all investigated sources, with the exceptions of 4C +21.35 and PKS1441+25. In terms of the overall jet power, particle energy is the dominant contributor, and the observed blazar radiation cannot be solely attributed to the magnetic field, except in the case of 4C +21.35. Consequently,magnetic reconnection is unlikely to be the primary mechanism behind particle acceleration in these systems.

关键词： galaxies: active galaxies: jets gamma-rays: galaxies

Chiral phonon activated spin Seebeck effect in chiral materials

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Science China(physics,Mechanics & Astronomy) 2024年第3期67卷 149-155页

作者： Xiao Li Jinxin Zhong Jinluo Cheng Hao Chen Huiqian Wang Jun Liu Dali Sun Lifa Zhang Jun Zhou Phonon Engineering Research Center of Jiangsu Province Center for Quantum Transport and Thermal Energy ScienceSchool of Physics and TechnologyNanjing Normal UniversityNanjing 210023China Center for Phononics and Thermal Energy Science China-EU Joint Lab for NanophononicsSchool of Physics Science and EngineeringTongji UniversityShanghai 200092China Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of ScienceChangchun 130033China Department of Mechanical and Aerospace Engineering North Carolina State UniversityRaleigh NC 27606USA Department of physics North Carolina State UniversityRaleigh NC 27695USA Organic and Carbon Electronics Laboratories(ORaCEL) North Carolina State UniversityRaleigh NC 27606USA

Efficient generation of spin polarization is very important for spintronics and quantum computation. In chiral materials without magnetic order nor spin-orbit coupling, we find a new spin selectivity effect—chiral phonon activated spin Seebeck(CPASS)effect. Starting with the nonequilibrium distribution of chiral phonons under a temperature gradient, the CPASS coefficients are computed based on the Boltzmann transport theory. With both the phonon-drag and band transport contributions, the spin accumulations generated by the CPASS effect exhibit quadratic dependence on the temperature gradient. The strength of the CPASS effect and the relative magnitude of both contributions are tunable by the chemical potential modulation. The CPASS effect, which gives a promising explanation on the traditional chiral-induced spin selectivity effect, provides opportunities for the exploration of advanced spintronic devices based on chiral materials even in the absence of any magnetic order and spin-orbit coupling.

关键词： spin Seebeck effect chiral phonon phonon-drag contribution efficient spin generation

Extraterrestrial Life in the Thermosphere: Plasmas, UAP, Pre-Life, Fourth State of Matter

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Journal of Modern physics 2024年第3期15卷 322-376页

作者： R. Joseph C. Impey O. Planchon R. del Gaudio M. Abu Safa A. R. Sumanarathna E. Ansbro D. Duvall G. Bianciardi C. H. Gibson R. Schild Astrobiology Research Center California USA Department of Astronomy University of Arizona Tucson USA Biogéosciences Laboratory University of Burgundy Dijon France Department of Biology University of Naples Federico II Naples Italy Department of Applied physics Palestine Polytechnic University Hebron Palestine Department of Research and Innovation Eco Astronomy International Research Center Tetouan Morocco Space Exploration Ltd. Boyle County Roscommon Ireland Department of Zoology Oklahoma State University (Emeritus) Stillwater USA Department of Science and Medicine Università Degli Studi di Siena Tuscany Italy Center for Astrophysics and Space Sciences University of California (Emeritus) San Diego USA Center for Astrophysics Harvard-Smithsonian (Emeritus) Cambridge USA

“Plasmas” up to a kilometer in size and behaving similarly to multicellular organisms have been filmed on 10 separate NASA space shuttle missions, over 200 miles above Earth within the thermosphere. These self-illuminated “plasmas” are attracted to and may “feed on” electromagnetic radiation. They have different morphologies: 1) cone, 2) cloud, 3) donut, 4) spherical-cylindrical;and have been filmed flying towards and descending from the thermosphere into thunderstorms;congregating by the hundreds and interacting with satellites generating electromagnetic activity;approaching the Space Shuttles. Computerized analysis of flight path trajectories documents these plasmas travel at different velocities from different directions and change their angle of trajectory making 45°, 90°, and 180° shifts and follow each other. They’ve been filmed accelerating, slowing down, stopping, congregating, engaging in “hunter-predatory” behavior and intersecting plasmas leaving a plasma dust trail in their wake. Similar life-like behaviors have been demonstrated by plasmas created experimentally. “Plasmas” may have been photographed in the 1940s by WWII pilots (identified as “Foo fighters”);repeatedly observed and filmed by astronauts and military pilots and classified as Unidentified Aerial—Anomalous Phenomenon. Plasmas are not biological but may represent a form of pre-life that via the incorporation of elements common in space, could result in the synthesis of RNA. Plasmas constitute a fourth state of matter, are attracted to electromagnetic activity, and when observed in the lower atmosphere likely account for many of the UFO-UAP sightings over the centuries.

关键词： Extraterrestrials Plasmas Dusty Plasmas Extremophiles Life in Space Abiogenesis Origins of Life RNA World

Origin of tradeoff between movement velocity and attachment duration of kinesin motor on a microtubule

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Chinese physics B 2024年第2期33卷 557-566页

作者：刘玉颖张志强 Department of physics College of ScienceChina Agricultural UniversityBeijing 100083China Basic Ministry Space Engineering UniversityBeijing 101416China

Kinesin-1 motor protein is a homodimer containing two identical motor domains connected by a common long coiledcoil stalk via two flexible neck linkers. The motor can step on a microtubule with a velocity of about 1 μm·s-1and an attachment duration of about 1 s under physiological conditions. The available experimental data indicate a tradeoff between velocity and attachment duration under various experimental conditions, such as variation of the solution temperature,variation of the strain between the two motor domains, and so on. However, the underlying mechanism of the tradeoff is unknown. Here, the mechanism is explained by a theoretical study of the dynamics of the motor under various experimental conditions, reproducing quantitatively the available experimental data and providing additional predictions. How the various experimental conditions lead to different decreasing rates of attachment duration versus velocity is also explained.

关键词： motor protein velocity detachment time processivity

Critical behavior of quasi-two-dimensional ferromagnet Cr_(1.04)Te_2

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Chinese physics B 2024年第7期33卷 87-94页

作者：钮伟宋沁心常世琦王敏袁奎高嘉程王硕王振东刘凯斐刘萍徐永兵张晓倩普勇 Jiangsu Provincial Engineering Research Center of Low Dimensional physics and New Energy&School of Science Nanjing University of Posts and TelecommunicationsNanjing 210023China School of Electronic Science and Engineering Nanjing UniversityNanjing 210023China Key Laboratory of Quantum Materials and Devices of Ministry of Education School of PhysicsSoutheast UniversityNanjing 211189China

The self-intercalation of Cr into pristine two-dimensional(2D) van der Waals ferromagnetic CrTe_2,which forms chromium tellurides(Cr_xTe_2),has garnered interest due to their remarkable magnetic characteristics and the wide variety of chemical compositions available.Here,comprehensive basic characterization and magnetic studies are conducted on quasi-2D ferromagnetic Cr_(1.04)Te_2 crystals.Measurements of the isothermal magnetization curves are conducted around the critical temperature to systematically investigate the critical behavior.Specifically,the critical exponents β=0.2399,γ=0.859,and δ=4.3498,as well as the Curie temperature T_C=249.56 K,are determined using various methods,including the modified Arrott plots,the Kouvel-Fisher method,the Widom scaling method,and the critical isotherm analysis.These results indicate that the tricritical mean-field model accurately represents the critical behavior of Cr_(1.04)Te_2.A magnetic phase diagram with tricritical phenomenon is thus constructed.Further investigations confirm that the critical exponents obtained conform to the scalar equation near T_C,indicating their self-consistency and reliability.Our work sheds light on the magnetic properties of quasi-2D Cr_(1.04)Te_2,broadening the scope of the van der Waals crystals for developments of future spintronic devices operable at room temperature.

关键词： critical behavior van der Waals magnets self-intercalation magnetic measurement

Engineering phonon thermal transport in few-layer PdSe_(2)

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Frontiers of physics 2024年第3期19卷 135-141页

作者： Meilin Li Huanhuan Sun Jun Zhou Yunshan Zhao Phonon Engineering Research Center of Jiangsu Province Center for Quantum Transport and Thermal Energy ScienceInstitute of Physics Frontiers and Interdisciplinary SciencesSchool of Physics and TechnologyNanjing Normal UniversityNanjing 210023China

Engineering phonon transport in low-dimensional materials has great significance not only for fundamental research,but also for thermal management applications of electric devices.However,due to the difficulties of micro and nano processing and characterization techniques,the work on tuning phonon transport at nanoscale are scarce.In this work,by introducing Ar+plasma,we probed the phonon transport in two-dimensional(2D)layered semiconductor PdSe_(2)under different defect concentrations.By using thermal bridge method,the thermal conductivity was measured to decrease by 50%after a certain Ar+irradiation,which implied a possible phase transition.Moreover,Raman characterizations were performed to show that the Raman sensitive peaks of PdSe_(2)was red-shifted and finally became disappeared with the increase of defect concentration.“Defect engineering”proves be a practical strategy in tuning the phonon thermal transport in low-dimensional materials,thus providing guidance for potential application in designing thermoelectric devices with various emerging materials.

关键词： phonon transport PdSe_(2) defects thermal bridge method

Light People:Prof.Kei May Lau,newly elected US NAE member in Hong Kong,talks about future of photonics and women in science

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Light(Science & Applications) 2024年第4期13卷 602-608页

作者： Yating Wan Chenzi Guo Electrical and Computer Engineering the ComputerElectrical and Mathematical Sciences and Engineering DivisionKing Abdullah University of Science and Technology23955-6900 ThuwalSaudi Arabia Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of SciencesChangchunChina

Editorial Photonics technology remains a driving force in today’s scientific landscape,marked by continuous innovation and crossdisciplinary relevance.In an enlighting conversation with Light:Science&Applications,Prof.Kei May Lau,a pioneer in photonics research,shares her deep insights on the evolution of technologies of LEDs,lasers,challenges of hetero-epitaxy,and the future of micro-LEDs and quantum dot lasers.Recently honored as a member of the US National Academy of Engineering(NAE)for her significant contributions to photonics and electronics using III-V semiconductors on silicon,Prof.Lau stands out as the sole Hong Kong scholar inducted into the NAE this year,joining 114 new and 21 international members.In this exclusive Light People interview,Prof.Lau shares her journey as a pioneering woman in engineering,her commitment to mentorship and academia,and her perspective on advancing female representation in science.The summary provided is distilled from Prof.Lau’s thoughtful responses during the interview.For a deeper exploration of Prof.Lau’s experiences and advice,the full interview is available in the Supplementary material.

关键词： interview lighting driving