Science China Physics, Mechanics & Astronomy最新文献

{"title":"The machine learning implementation and theoretical foundations of intelligent control of accelerator particle beams","authors":"XueQing Yan","doi":"10.1007/s11433-024-2525-8","DOIUrl":"10.1007/s11433-024-2525-8","url":null,"abstract":"","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"68 2","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142778182","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":"Reveal short range interactions between u/d quarks in the NN, D03, and D30 systems","authors":"Qi-Fang Lü,&nbsp;Yu-Bing Dong,&nbsp;Peng-Nian Shen,&nbsp;Zong-Ye Zhang","doi":"10.1007/s11433-024-2541-9","DOIUrl":"10.1007/s11433-024-2541-9","url":null,"abstract":"<div><p>The dynamic mechanism of short range interactions between <i>u/d</i> quarks remains an open and challenging problem. In order to reveal this quark dynamics, we perform a systematic analysis of <i>NN</i>, <i>D</i>₀₃, and <i>D</i>₃₀ systems in the (extended) chiral SU(3) constituent quark models. By comparing results calculated with different models and different parameter sets, the effects of one gluon exchange and vector meson exchange terms are carefully examined. The results indicate that the vector meson exchange interactions dominate the short range interactions between <i>u/d</i> quarks, whereas the small residual one gluon exchange coupling strength is also allowed.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"68 3","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142762044","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 the special angle in twisted bilayer MoS2 via angle-dependent scanning tunneling microscopy studies","authors":"Xueying Liu,&nbsp;Shiying Liu,&nbsp;Yulong Xiao,&nbsp;Chang Xu,&nbsp;Jiaxin Wu,&nbsp;Kaihui Li,&nbsp;Si-Yu Li,&nbsp;Anlian Pan","doi":"10.1007/s11433-024-2529-9","DOIUrl":"10.1007/s11433-024-2529-9","url":null,"abstract":"<div><p>Twisted transition metal dichalcogenides (TMDs) homo-bilayers host unique quantum properties, which can be tuned by interlayer twist angle <i>θ</i>. However, the systematic evolution of their typical electronic properties with respect to the twist angle <i>θ</i>, which is crucial for identifying the “special angle” analogous to the “magic angle” of twisted bilayer graphene in correlation physics studies, remains incompletely understood. Here, via scanning tunneling microscopy (STM) and spectroscopy (STS), we investigate the variation of the moiré potential, flat band, and layer polarization characteristics across a wide range of twist angle <i>θ</i> in twisted bilayer MoS₂ (TB-MoS₂). The moiré potential of the valence band exhibits a non-monotonic variation with <i>θ</i>, peaking at a maximum value up to 204 meV at <i>θ</i>∼1.7°. Concurrently, at the same <i>θ</i>, the bandwidth of the flat band at the Γ_V point of the valence band attains its minimum, precisely signifying the “special angle” <i>θ</i>_c∼1.7° in TB-MoS₂. Interestingly, layer polarization in the moiré superlattice is spatially visualized through the distribution of local density of states (LDOS) at the energies of both Γ_V and K_V points of the valence band, where the polarization degree at the Γ_V point demonstrates a close dependency on <i>θ</i>. Our findings deepen understanding of twist-angle effect in TMDs, advancing both fundamental physics and practical application.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"68 2","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142758015","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":"New Taub-NUT black holes with massive spin-2 hair","authors":"Yu-Qi Chen,&nbsp;Hai-Shan Liu","doi":"10.1007/s11433-024-2540-4","DOIUrl":"10.1007/s11433-024-2540-4","url":null,"abstract":"<div><p>We consider Einstein gravity extended with quadratic curvature invariants, within which the well-known Ricci-flat Taub-NUT black hole remains a solution. An analysis of the unstable Lichnerowicz modes in the Taub-NUT background enables us to identify the mass and NUT parameters (<i>m, n</i>) where new Taub-NUT black holes can emerge. We then adopt numerical techniques to construct these new Taub-NUT black holes, which bifurcate away from the Ricci-flat ones. Unlike the Ricci-flat Taub-NUT, there can exist two new black holes for an appropriate given temperature, making it a total of three if we include the Ricci-flat one.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"68 2","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142737140","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":"Great influence of demagnetization history on internal interaction and magnetization process of mischmetal-based magnets","authors":"Dan Liu,&nbsp;Jiefu Xiong,&nbsp;Lichen Wang,&nbsp;Xinqi Zheng,&nbsp;Xin Ming,&nbsp;Jiaying Jin,&nbsp;Jiazheng Hao,&nbsp;He Bai,&nbsp;Zhenxing Li,&nbsp;Tongyun Zhao,&nbsp;Fengxia Hu,&nbsp;Jirong Sun,&nbsp;Jun Shen,&nbsp;Baogen Shen","doi":"10.1007/s11433-024-2521-9","DOIUrl":"10.1007/s11433-024-2521-9","url":null,"abstract":"<div><p>The magnetization process and corresponding magnetization curve are usually used to analyze the coercivity mechanism of Nd-Fe-B based sintered magnet. However, different demagnetization histories will seriously influence the magnetization curve, leading to an inaccurate understanding and analysis of magnetization process. In this work, we investigated the magnetization behavior of multi-main phase (MMP) magnets with thermal demagnetized and alternating current demagnetized states. Recoil curves of initial magnetization process and demagnetization process of thermal demagnetized magnets reflect the movement of domain walls inside the grains and the magnetization interaction between the grains, respectively. It is noted that the former process cannot represent the magnetization reversal of the entire magnet, which is not appropriate to analyze coercivity mechanism alone. While the recoil curves of both two processes of AC demagnetized magnets can illustrate the magnetization reversal of the entire grains and the interaction between grains. Magneto-optical Kerr microscope shows that the grains of thermal demagnetized magnets are in multi-domain states, and the grains of AC demagnetized magnets are almost in single-domain states. Domain walls of thermal demagnetized magnets move easily within the grains, which is more conducive to magnetization saturation in industrial production. In addition, the minorloops of thermal demagnetized magnets can independently represent the transition of grains from multi-domain to single-domain and the demagnetization of single-domain grains, which is equivalent to characterizing the internal interactions by recoil curves. The investigation of magnetization characteristics of MMP sintered magnets starting from different demagnetized states is helpful to further understand the internal interaction and magnetic hardening mechanism.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"68 2","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142737071","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":"Quantum purification for coherent states and its application","authors":"Lei Wang,&nbsp;Geng Chai,&nbsp;Zhengwen Cao,&nbsp;Xinlei Chen,&nbsp;Kexin Liang,&nbsp;Jinye Peng","doi":"10.1007/s11433-024-2533-4","DOIUrl":"10.1007/s11433-024-2533-4","url":null,"abstract":"<div><p>The inevitable decoherence of quantum states leaks information to the environments and reduces the practical performance of quantum-information protocols. Quantum purification of coherent states provides an easy-to-implement approach to decouple from the environments utilizing the correlation of several copies. However, repeated transmission of quantum states reduces the randomness of the collectivity and generates security vulnerabilities. In this paper, we propose a modified purification scheme and apply it to the continuous-variable quantum secure direct communication (CV-QSDC) protocol based on coherent states. The designed purification scheme improves the security capacity of communication systems through the effective suppression of excess noises, accompanied by the maintenance of source-side stochasticity. We conduct a proof-of-principle experiment of the purification scheme in the CV-QSDC system. The appearance of transmitted quantum states in phase space and two-dimensional Gaussian distributions have high goodness of fit at two copies. The security capability of this system is improved by 43.6% as the excess noise is reduced to 0.58 times the original noise by purification.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"68 2","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142714300","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":"Three-dimensional fracture of UO2 ceramic pellets by phase field modeling","authors":"Wei Xiong,&nbsp;Xuan Ye,&nbsp;Hongzhang Cheng,&nbsp;Xiaoming Liu","doi":"10.1007/s11433-024-2509-2","DOIUrl":"10.1007/s11433-024-2509-2","url":null,"abstract":"<div><p>Fracture is the primary failure type for the UO₂ ceramic pellets, which are operated under irradiation and thermal processes, and physically confined by the cladding. In this work, by combining closely coupled physical processes of heat conduction, heat transfer, and mechanical deformation with the cohesive phase field framework, we proposed a high-precision modeling of quasi-static cracking of three-dimensional (3D) UO₂ ceramic fuel pellets under high temperature and irradiation. The simulation results agree well with the experimental results, indicating that the proposed method has the potential to capture 3D crack modes in the interested time range. Further, we studied the relation of the 3D fracture patterns of fuel pellets with the peak power densities. It was found that the power level plays a critical role in determining the competition between radial and circumferential cracks, as well as transverse penetrating cracks.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"68 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142714298","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":"PandaX-xT—A deep underground multi-ten-tonne liquid xenon observatory","authors":"Abdusalam Abdukerim,&nbsp;Zihao Bo,&nbsp;Wei Chen,&nbsp;Xun Chen,&nbsp;Chen Cheng,&nbsp;Zhaokan Cheng,&nbsp;Xiangyi Cui,&nbsp;Yingjie Fan,&nbsp;Deqing Fang,&nbsp;Lisheng Geng,&nbsp;Karl Giboni,&nbsp;Linhui Gu,&nbsp;Xunan Guo,&nbsp;Xuyuan Guo,&nbsp;Zhichao Guo,&nbsp;Chencheng Han,&nbsp;Ke Han,&nbsp;Changda He,&nbsp;Jinrong He,&nbsp;Di Huang,&nbsp;Junting Huang,&nbsp;Zhou Huang,&nbsp;Ruquan Hou,&nbsp;Yu Hou,&nbsp;Xiangdong Ji,&nbsp;Yonglin Ju,&nbsp;Chenxiang Li,&nbsp;Jiafu Li,&nbsp;Mingchuan Li,&nbsp;Shuaijie Li,&nbsp;Tao Li,&nbsp;Qing Lin,&nbsp;Jianglai Liu,&nbsp;Congcong Lu,&nbsp;Xiaoying Lu,&nbsp;Lingyin Luo,&nbsp;Yunyang Luo,&nbsp;Wenbo Ma,&nbsp;Yugang Ma,&nbsp;Yajun Mao,&nbsp;Yue Meng,&nbsp;Xuyang Ning,&nbsp;Binyu Pang,&nbsp;Ningchun Qi,&nbsp;Zhicheng Qian,&nbsp;Xiangxiang Ren,&nbsp;Nasir Shaheed,&nbsp;Xiaofeng Shang,&nbsp;Xiyuan Shao,&nbsp;Guofang Shen,&nbsp;Lin Si,&nbsp;Wenliang Sun,&nbsp;Yi Tao,&nbsp;Anqing Wang,&nbsp;Meng Wang,&nbsp;Qiuhong Wang,&nbsp;Shaobo Wang,&nbsp;Siguang Wang,&nbsp;Wei Wang,&nbsp;Xiuli Wang,&nbsp;Xu Wang,&nbsp;Zhou Wang,&nbsp;Yuehuan Wei,&nbsp;Mengmeng Wu,&nbsp;Weihao Wu,&nbsp;Yuan Wu,&nbsp;Mengjiao Xiao,&nbsp;Xiang Xiao,&nbsp;Binbin Yan,&nbsp;Xiyu Yan,&nbsp;Yong Yang,&nbsp;Chunxu Yu,&nbsp;Ying Yuan,&nbsp;Zhe Yuan,&nbsp;Youhui Yun,&nbsp;Xinning Zeng,&nbsp;Minzhen Zhang,&nbsp;Peng Zhang,&nbsp;Shibo Zhang,&nbsp;Shu Zhang,&nbsp;Tao Zhang,&nbsp;Wei Zhang,&nbsp;Yang Zhang,&nbsp;Yingxin Zhang,&nbsp;Yuanyuan Zhang,&nbsp;Li Zhao,&nbsp;Jifang Zhou,&nbsp;Ning Zhou,&nbsp;Xiaopeng Zhou,&nbsp;Yong Zhou,&nbsp;Yubo Zhou,&nbsp;Zhizhen Zhou,&nbsp;PandaX Collaboration","doi":"10.1007/s11433-024-2539-y","DOIUrl":"10.1007/s11433-024-2539-y","url":null,"abstract":"<div><p>We propose a major upgrade to the existing PandaX-4T experiment at the China Jinping Underground Laboratory. The new experiment, PandaX-xT, will be a multi-ten-tonne liquid xenon, ultra-low background, and general-purpose observatory. The full-scaled PandaX-xT contains a 43-t liquid xenon active target. Such an experiment will significantly advance our fundamental understanding of particle physics and astrophysics. The sensitivity of dark matter direct detection will be improved by nearly two orders of magnitude compared to the current best limits, approaching the so-called “neutrino floor” for a dark matter mass above 10 GeV/c², providing a key test to the Weakly Interacting Massive Particle paradigm. By searching for the neutrinoless double beta decay of ¹³⁶Xe isotope in the detector, the effective Majorana neutrino mass can be measured to a 10–41 meV/c² sensitivity, providing a key test to the Dirac/Majorana nature of neutrinos. Astrophysical neutrinos and other ultra-rare interactions can also be measured and searched for with an unprecedented background level, opening up new windows of discovery. Depending on the findings, PandaX-xT will seek the next stage upgrade utilizing isotopic separation of natural xenon.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"68 2","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142714299","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":"Targets capture by distributed active swarms via bio-inspired reinforcement learning","authors":"Kun Xu,&nbsp;Yue Li,&nbsp;Jun Sun,&nbsp;Shuyuan Du,&nbsp;Xinpeng Di,&nbsp;Yuguang Yang,&nbsp;Bo Li","doi":"10.1007/s11433-024-2494-0","DOIUrl":"10.1007/s11433-024-2494-0","url":null,"abstract":"<div><p>Natural swarms arranged from cells to herds are usually decentralized but display intriguing collective intelligence in coordinating individuals across large scales to efficiently achieve their common goals. Learning from nature may provide new strategies for controlling collective dynamics of synthetic swarms to accomplish specific functions. Here, we present a bio-inspired computational framework that steers distributed active swarms to collectively capture and merge targets via reinforcement learning. We exploit collective milling structures of natural herds to cage the targets, and adopt a switching control policy inspired by sperms’ chiral dynamics to optimize the trajectories of individuals, through which the active swarms can self-organize to enclose single or multiple distant targets in a dynamical, adaptive and scalable manner. There exists a critical swarm size, beyond which the excessive competition between agents would generate large mechanical forces, leading to capture instability but enabling the transition from short-distance to long-distance merging capture of multiple targets. This work provides physical insights into distributed active swarms and could offer a multilevel, decentralized strategy toward controlling swarm robotics in wide applications such as bio-medical devices, machine immunity, and target clearance.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"68 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142691878","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":"Unraveling atomistic and electronic origins of multiaxial magnetic anisotropy","authors":"Boyu Liu,&nbsp;Xueyang Li,&nbsp;Junsheng Feng,&nbsp;Changsong Xu,&nbsp;Hongjun Xiang","doi":"10.1007/s11433-024-2518-y","DOIUrl":"10.1007/s11433-024-2518-y","url":null,"abstract":"<div><p>Multiaxial magnetic anisotropy (MA) refers to the phenomenon that multiple axes of the magnetic crystal correspond to different energy minima. Compared with the common uniaxial magnetic anisotropy, multiaxial MA facilitates novel forms of applications in spintronics. Here, by combining the first-principles-based spin Hamiltonian and tight-binding (TB) method, we reveal the microscopic origins, instead of the common phenomenological understanding, of biaxial MA and triaxial MA. In the example system of NiO, it is found that the multiple minima result from the fourth-order and the sixth-order single ion interactions, while the difference between [110] and <span>([1bar{1}0])</span> directions originates from a second-order bond-dependent anisotropic pair interaction (i.e., the so-called Gamma interaction). Moreover, through the application of a newly developed general spin dependent TB approach, it is revealed that the triaxial MA arises from the special spin-orbital entangled Hund term, which is different from the orbital-independent Hund term in the usual Slater Koster TB method. Our work thus not only leads to a thorough understanding of the multiaxial MA in NiO, but also establishes a methodology that can be widely used to explore the microscopic origins of MA in different magnets.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"68 2","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142714363","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}