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High-Tc superconductor fe(Se,Te) monolayer:an intrinsic,scalable and electrically tunable Majorana platform

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National Science review 2022年第3期9卷 11-18页

作者： Xianxin Wu Xin Liu ronny Thomale Chao-Xing Liu institut für Theoretische Physik und astrophysik Julius-Maximilians-Universit?t Würzburg School of Physics Huazhong University of Science and Technology Wuhan National High Magnetic field Center Huazhong University of Science and Technology Department of Physics the Pennsylvania State University

Iron-based superconductors have been identified as a novel platform for realizing Majorana zero modes(MZMs) without heterostructures, due to their intrinsic topological properties and high-Tc superconductivity. In the two-dimensional limit, the feTe1-xSexmonolayer, a topological band inversion has recently been experimentally observed. Here, we propose to create MZMs by applying an in-plane magnetic field to the feTe1-xSexmonolayer and tuning the local chemical potential via electric gating.Owing to the anisotropic magnetic couplings on edges, an in-plane magnetic field drives the system into an intrinsic high-order topological superconductor phase with Majorana corner modes. furthermore, MZMs can occur at the domain wall of chemical potentials at either one edge or certain type of tri-junction in the two-dimensional bulk. Our study not only reveals the feTe1-xSexmonolayer as a promising Majorana platform with scalability and electrical tunability and within reach of contemporary experimental capability,but also provides a general principle to search for realistic realization of high-order topological superconductivity.

关键词： high-order topological superconductivity Majorana zero modes iron-based superconductors

Mock catalogues for large surveys:Lessons from Gaia and implications for CSST

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Science China(Physics,Mechanics & Astronomy) 2023年第11期66卷 239-240页

作者： Tristan Cantat-Gaudin Max-Planck-institut für astronomie Heidelberg69117Germany

Experience in large stellar surveys,such as Gaia,has shown that synthetic catalogues are very useful for preparing the data and evaluating scientific results(see the Gaia Universe model snapshot,ref.[1],as an example).This experience holds especially for complex datasets that provide not only positions and apparent magnitudes,but also proper motions,multi-band photometry,and spectroscopy.

关键词： spectroscopy survey holds

预言X(3872)的伴随态D_(s)(*)D_(s)(*)束缚态

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Science Bulletin 2021年第13期66卷 1288-1295,M0003,M0004页

作者：孟璐王波朱世琳 ruhr-Universität Bochum Fakultät für Physik und AstronomieInstitut für Theoretische Physik IID-44780 BochumGermany Center of High Energy Physics Peking UniversityBeijing 100871China School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking UniversityBeijing 100871China

本文研究了双介子系统中的SU(3)味道对称性,重夸克自旋对称性及它们的破缺效应,进而基于SU(3)味道对称性和重夸克自旋对称下的两个前提证明了[D_(s)(*)D_(s)(*)]^(0++),[D_(s)(*)D_(s)/D_(s)D_(s)(*)]^(1+-)和[D_(s)(*)D_(s)(*)]^(+-)束缚态的存在.第一个前提,X(3872)是D*D/DD*的弱束缚态,可以被它的质量和衰变分支比所支持.第二个前提,存在[DsDs]^(0++)的束缚态,被格点QCD的计算以及LHCb合作组观测到的χ_(c0)(3930)所支持.这些束缚态的预言有望在未来B→D_(s)(*)D_(s)(*)h的实验分析中找到(h代表轻强子).[D_(s)(*)D_(s)(*)]^(0++)束缚态也有望在B→J/ψϕK的衰变J/ψϕ的末态中重建得到.

关键词：束缚态衰变分支比格点QCD SU(3) 重夸克强子末态破缺

Millimeter gap contrast as a probe for turbulence level in protoplanetary disks

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Science China(Physics,Mechanics & Astronomy) 2022年第12期65卷 131-144页

作者： Yao Liu Gesa H.-M.Bertrang Mario flock Giovanni P.rosotti Ewine f.van Dishoeck Yann Boehler Stefano facchini Can Cui Sebastian Wolf Min fang Max-Planck-institut für Extraterrestrische Physik Garching85748Germany Purple Mountain Observatory&Key Laboratory for radio Astronomy Chinese Academy of SciencesNanjing210023China Max-Planck-institut für astronomie HeidelbergD-69117Germany Leiden Observatory Leiden UniversityLeidenNL-2300the Netherlands School of Physics and Astronomy University of LeicesterLeicesterLE17RHUK UniversitéGrenoble Alpes French National Centre for Scientific ResearchInstitute for Planetary Sciences and AstrophysicsGrenobleGrenobleF-38000France European Southern Observatory Garching85748Germany Department of Applied Mathematics and Theoretical Physics University of CambridgeCentre for Mathematical SciencesCambridgeCB3 OWAUK institut für Theoretische Physik und astrophysik Christian-Albrechts-Universität zu kielKiel24118Germany

Turbulent motions are believed to regulate angular momentum transport and influence dust evolution in protoplanetary disks.Measuring the strength of turbulence is challenging through gas line observations because of the requirement for high spatial and spectral resolution data,and an exquisite determination of the temperature.In this work,taking the well-known HD 163296 disk as an example,we investigated the contrast of gaps identified in high angular resolution continuum images as a probe for the level of turbulence.With self-consistent radiative transfer models,we simultaneously analyzed the radial brightness profiles along the disk major and minor axes,and the azimuthal brightness profiles of the B67 and B100 rings.By fitting all the gap contrasts measured from these profiles,we constrained the gas-to-dust scale height ratioΛto be 3.0^(+0.3)_(−0.8),1.2^(+0.1)_(−0.1),and≥6.5 for the D48,B67,and B100 regions,respectively.The varying gas-to-dust scale height ratios indicate that the degree of dust settling changes with radius.The inferred values forΛtranslate into a turbulence level of α_(turb)regions,which is consistent with previous upper limits set by gas line observations.However,turbulent motions in the B67 ring are strong with α_(turb)∼1.2×10^(−2).Due to the degeneracy betweenΛand the depth of dust surface density drops,the turbulence strength in the D86 gap region is not constrained.

关键词： protoplanetary disks radiative transfer planet formation

预言X(3872)的伴随态■s* Ds*束缚态(英文)

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Science Bulletin 2021年第13期66卷 1288-1295页

作者：孟璐王波朱世琳 ruhr-Universit?t Bochum Fakult?t für Physik und Astronomie Institut für Theoretische Physik Ⅱ Center of High Energy Physics Peking University School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking University

本文研究了双介子系统中的SU(3)味道对称性,重夸克自旋对称性及它们的破缺效应,进而基于SU(3)味道对称性和重夸克自旋对称下的两个前提证明了■束缚态的存在.第一个前提,X(3872)是■的弱束缚态,可以被它的质量和衰变分支比所支持.第二... 详细信息

本文研究了双介子系统中的SU(3)味道对称性,重夸克自旋对称性及它们的破缺效应,进而基于SU(3)味道对称性和重夸克自旋对称下的两个前提证明了■束缚态的存在.第一个前提,X(3872)是■的弱束缚态,可以被它的质量和衰变分支比所支持.第二个前提,存在■的束缚态,被格点QCD的计算以及LHCb合作组观测到的χC0(3930)所支持.这些束缚态的预言有望在未来■的实验分析中找到(h代表轻强子).■束缚态也有望在B→J/ψΦK的衰变J/ψΦ的末态中重建得到.

关键词： SU(3) flavor symmetry Hadronic molecule X(3872) Tetraquark

Searching for the Highest Energy of Pulsation and Critical Luminosity of Swift J0243.6+6124 Observed by Insight-HXMT

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research in Astronomy and Astrophysics 2024年第5期24卷 63-71页

作者： Qing-Xia Zhao Xian Hou Ming-Yu Ge Shuang-Nan Zhang Yun-Xiang Xiao You-Li Tuo Zi-Xu Yang Ling-Da Kong Jin-Lu Qu Shu Zhang Jian-Cheng Wang Yunnan Observatories Chinese Academy of Sciences Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of Sciences University of Chinese Academy of Sciences Chinese Academy of Sciences Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Institut für Astronomie und Astrophysik School of Physics and Optoelectronic Engineering Shandong University of Technology

Owing to the broad energy coverage of Insight-HXMT in the hard X-ray band,we detected the highest energy of pulsation exceeding 200 keV around the 2017–2018 outburst peak of the first Galactic pulsating ultraluminous X-ray source (PULX) Swift J0243.6+6124,which is the highest energy detected from PULXs to date.We also obtained the highest energy of pulsation of every exposure during the outburst in 2017–2018,and found the highest energy is roughly positively correlated with luminosity.Using our newly developed method,we identified the critical luminosity being 4×1038erg s-1when the main peaks of the low and high energy pulse profiles became aligned,which separates the fan-beam dominated and pencil-beam dominated accretion regimes.Above the critical luminosity,the phase of the main peak shifted gradually from 0.5 to 0.8 until the outburst peak in al energy bands is reached,which is in agreement with the phase shift found previously at low energies.Our result is consistent with what is derived from spectral analysis.

关键词： (stars:) pulsars: individual (Swift J0243.6+6124) stars: neutron X-rays: binaries

A comparison of approaches in fitting continuum SEDs

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research in Astronomy and Astrophysics 2013年第4期13卷 420-434页

作者： Yao Liu David Madlener Sebastian Wolf Hong-Chi Wang Purple Mountain Observatory and Key Laboratory for radio Astronomy Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences institut fr Theoretische Physik und astrophysik Universitt zu Kiel

We present a detailed comparison of two approaches, the use of a precalculated database and simulated annealing （SA）, for fitting the continuum spectral energy distribution （SED） of astrophysical objects whose appearance is dominated by surrounding dust. While pre-calculated databases are commonly used to model SED data, only a few studies to date employed SA due to its unclear accuracy and convergence time for this specific problem. from a methodological point of view, different approaches lead to different fitting quality, demand on computational resources and calculation time. We compare the fitting quality and computational costs of these two approaches for the task of SED fitting to provide a guide to the practitioner to find a compromise between desired accuracy and available resources. To reduce uncertainties inherent to real datasets, we introduce a reference model resembling a typical circumstellar system with 10 free parameters. We derive the SED of the reference model with our code MC3 D at 78 logarithmically distributed wavelengths in the range [0.3 μm, 1.3 mini and use this setup to simulate SEDs for the database and SA. Our result directly demonstrates the applicability of SA in the field of SED modeling, since the algorithm regularly finds better solutions to the optimization problem than a precalculated database. As both methods have advantages and shortcomings, a hybrid approach is preferable. While the database provides an approximate fit and overall probability distributions for all parameters deduced using Bayesian analysis, SA can be used to improve upon the results returned by the model grid.

关键词： methods numerical - radiative transfer - protoplanetary disks

radiative transfer modeling of three T Tauri stars: selecting candidates for studying circumstellar disk evolution

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research in Astronomy and Astrophysics 2013年第7期13卷 841-848页

作者： Yao Liu Hong-Chi Wang Sebastian Wolf David Madlener Purple Mountain Observatory&Key Laboratory for radio Astronomy Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences institut für Theoretische Physik und astrophysik Universitt zu Kiel

We present modeling work on three young stellar objects that are promis-ing targets for future high-resolution observations to investigate circumstellar disk evolution. The currently available data comprise the spectral energy distribution from optical to millimeter wavelengths which allow constraining the structure of the cir-cumstellar disk using self-consistent radiative transfer models. The results suggest that the assumption of well-mixed dust and gas leads to overestimation of flux in the far-infrared. Observational and theoretical arguments suggest that an overall decrease in far-infrared excess can be explained by dust settling towards the midplane. A new disk model is hence employed to take the effect of dust sedimentation into account. The extended model satisfactorily reproduces all existing observations. The three tar-gets studied here therefore deserve follow-up observations to reveal the evolutionary state of their protoplanetary disks.

关键词： circumstellar matter - planetary systems： protoplanetary disks - ra-diative transfer

The GeV emission of PSr B1259–63 during its last three periastron passages observed by fermi-LAT

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research in Astronomy and Astrophysics 2018年第12期18卷 89-94页

作者： Zhi Chang Shu Zhang Yu-Peng Chen Long Ji Ling-Da Kong Cong-Zhan Liu Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China institut fur astronomie und astrophysik Kepler Center for Astro and Particle PhysicsEberhard Karls UniversitatSand 172076 TubingenGermany University of Chinese Academy of Sciences Beijing 100049China

PSr B1259–63 is a γ-ray emitting high mass X-ray binary system, in which the compact object is a millisecond pulsar.The system has an orbital period of 1236.7 d and shows peculiar γ-ray flares when the neutron star moves out of the stellar disk of the companion star.The γ-ray flare events were firstly discovered by using fermi-LAT around the 2010 periastron passage, which was repeated for the 2014 and 2017 periastron passages.We analyze the fermi-LAT data for all the three periastron passages and found that in each flare the energy spectrum can be represented well by a simple power law.The γ-ray light curves show that in 2010 and 2014 after each periastron there are two main flares,but in 2017 there are four flares including one precursor about 10 d after the periastron passage.The first main flares in 2010 and 2014 are located at around 35 d after the periastron passage, and the main flare in 2014 is delayed by roughly 1.7 d with respect to that in 2010.In the 2017 flare, the source shows a precursor about 10 d after the periastron passage, but the following two flares become weaker and lag behind those in 2010 by roughly 5 d.The strongest flares in 2017 occurred 58 d and 70 d after the periastron passage.These results challenge the previous models.

关键词： binaries:general pulsars:general gamma rays:general