检索结果-南通市图书馆

Primordial black holes and curvature perturbations from false vacuum islands

在线全文

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2024年第9期67卷 58-72页

作者： Rong-Gen Cai Yu-Shi Hao Shao-Jiang Wang 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 Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Asia Pacific center for theoretical physics Pohang 37673Republic of Korea

Recently,much attention has been focused on the false vacuum islands that are flooded by an expanding ocean of true-vacuum bubbles slightly later than most of the other parts of the *** delayed decay regions will accumulate locally larger vacuum energy density by staying in the false vacuum longer than those already transited into the true vacuum.A false vacuum island with thus acquired density contrast of a super-horizon size will evolve locally from radiation dominance to vacuum dominance,creating a local baby Universe that can be regarded effectively as a local closed *** such density contrasts of super-horizon sizes can ever grow large enough to exceed the threshold of gravitational collapse,primordial black holes will form similar to those collapsing curvature perturbations on super-horizon scales induced by small-scale enhancements during *** not,such density contrasts can still induce curvature perturbations potentially observable *** this paper,we revisit and elaborate on the generations of primordial black holes and curvature perturbations from delayed-decayed false vacuum islands during asynchronous first-order phase transitions with fitting formulas convenient for future model-independent studies.

关键词： first-order phase transitions primordial black holes curvature perturbations

同方期刊数据库

K-core attack, equilibrium K-core,and kinetically constrained spin system

在线全文

学校读者我要写书评

暂无评论

Chinese physics B 2024年第6期33卷 14-26页

作者：周海军 Institute of theoretical physics Chinese Academy of SciencesBeijing 100190China MinJiang Collaborative center for theoretical physics MinJiang UniversityFuzhou 350108China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China

Kinetically constrained spin systems are toy models of supercooled liquids and amorphous solids. In this perspective,we revisit the prototypical Fredrickson–Andersen(FA) kinetically constrained model from the viewpoint of K-core combinatorial optimization. Each kinetic cluster of the FA system, containing all the mutually visitable microscopic occupation configurations, is exactly the solution space of a specific instance of the K-core attack problem. The whole set of different jammed occupation patterns of the FA system is the configuration space of an equilibrium K-core problem. Based on recent theoretical results achieved on the K-core attack and equilibrium K-core problems, we discuss the thermodynamic spin glass phase transitions and the maximum occupation density of the fully unfrozen FA kinetic cluster, and the minimum occupation density and extreme vulnerability of the partially frozen(jammed) kinetic clusters. The equivalence between K-core attack and the fully unfrozen FA kinetic cluster also implies a new way of sampling K-core attack solutions.

关键词： Fredrickson–Andersen model K-core attack spin glass jamming

Gravitational wave footprints from Higgs-portal scalegenesis with multiple dark chiral scalars

在线全文

学校读者我要写书评

暂无评论

Chinese physics C 2024年第4期48卷 209-221页

作者： He-Xu Zhang Shinya Matsuzaki Hiroyuki Ishida center for theoretical physics and College of physics Jilin UniversityChangchun 130012China center for Liberal Arts and Sciences Toyama Prefectural UniversityToyama 939-0398Japan

We discuss the gravitational wave(GW)spectra predicted from the electroweak scalegenesis of the Higgs portal type with a large number of dark chiral flavors,which many flavor QCD would underlie and give the dynamical explanation of the negative Higgs portal coupling required to trigger the electroweak symmetry *** employ the linear-sigma model as the low-energy description of dark many flavor QCD and show that the model undergoes ultra-supercooling due to the produced strong first-order thermal phase transition along the(approximately realized)flat direction based on the Gildener-Weinberg *** through evaluation of the bubble nucleation/percolation,we address the reheating and relaxation processes,which are generically non-thermal and *** the reheating epoch in terms of the e-folding number,we propose proper formulae for the redshift effects on the GW frequencies and signal *** then turns out that the ultra-supercooling predicted from the Higgs-portal scalegenesis generically yields none of GW signals with the frequencies as low as nano Hz,unless the released latent heat is transported into another sector other than reheating the ***,models of this class prefer to give the higher frequency signals and still keeps the future prospected detection sensitivity,like at LISA,BBO,and DECIGO,*** also find that with large flavors in the dark sector,the GW signals are made further smaller and the peak frequencies *** phenomenological consequences related to the multiple chiral scalars include the prediction of dark pions with the mass much less than TeV scale,which is also briefly addressed.

关键词： gravitational wave electroweak scalegenesis many flavor QCD

Manipulation of band gap in 1T-TiSe_(2) via rubidium deposition

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese physics B 2024年第8期33卷 102-106页

作者：欧仪陈磊信子鸣任宇靖袁鹏浩王政国朱玉陈景芝张焱 international center for Quantum Materials School of PhysicsPeking UniversityBeijing 100871China

The 1T-TiSe_(2) is a two-dimensional charge-density-wave(CDW)material that attracts great interest.A small band gap locates at the Fermi level separating the Ti d-bands and Se p-bands,which makes 1T-TiSe_(2) a promising candidate for realizing excitonic ***,we studied the band gap in 1T-TiSe_(2) using angle-resolved photoemission spectroscopy(ARPES).Instead of only focusing on the in-plane band dispersions,we obtained the detailed band dispersions of both conduction and valance bands along the out-of-plane *** found that the conduction and valance bands split into multiple sub-bands in the CDW state due to band *** a result,the band gap between the Ti d-bands and Se p-bands reduces to~25 meV and becomes a direct gap in the CDW *** intriguingly,such band gap can be further reduced by the rubidium *** band structure becomes semimetallic in the rubidium-doped ***,exotic gapless behaviors were observed at the p-d band *** result characterized the band gap of 1T-TiSe_(2) in three-dimensional Brillouin zone with unpreceded *** also suggests a closing of band gap or a potential band inversion in 1T-TiSe_(2) driven by rubidium deposition.

关键词： angle-resolved photoemission spectroscopy metal–insulator transition transition metal dichalcogenides

Energy-information trade-off induces continuous and discontinuous phase transitions in lateral predictive coding

在线全文

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2024年第6期67卷 79-85页

作者： Zhen-Ye Huang Ruyi Zhou Miao Huang Hai-Jun Zhou Key Laboratory for theoretical physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China School of Optics and Photonics Beijing Institute of TechnologyBeijing 100081China Minjiang Collaborative center for theoretical physics Minjiang UniversityFuzhou 350108China

Lateral predictive coding is a recurrent neural network that creates energy-efficient internal representations by exploiting statistical regularity in sensory ***,we analytically investigate the trade-off between information robustness and energy in a linear model of lateral predictive coding and numerically minimize a free energy *** observed several phase transitions in the synaptic weight matrix,particularly a continuous transition that breaks reciprocity and permutation symmetry and builds cyclic dominance and a discontinuous transition with the associated sudden emergence of tight balance between excitatory and inhibitory *** optimal network follows an ideal gas law over an extended temperature range and saturates the efficiency upper bound of energy *** results provide theoretical insights into the emergence and evolution of complex internal models in predictive processing systems.

关键词： predictive coding recurrent neural network phase transition internal model free energy

Gravitational waves and primordial black hole productions from gluodynamics by holography

在线全文

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2024年第4期67卷 31-42页

作者： Song He Li Li Zhibin Li Shao-Jiang Wang center for theoretical physics and College of physics Jilin UniversityChangchun 130012China Max Planck Institute for Gravitational physics(Albert Einstein Institute) Golm 14476Germany 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 SciencesHangzhou 310024China Peng Huanwu Collaborative center for Research and Education Beihang UniversityBeijing 100191China School of physics and Microelectronics Zhengzhou UniversityZhengzhou 450001China

Understanding the nature of quantum chromodynamics(QCD)matter is important but challenging due to the presence of nonperturbative dynamics under extreme *** construct a holographic model describing the gluon sector of QCD at finite temperatures in the non-perturbative *** equation of state as a function of temperature is in good accordance with the lattice QCD ***,the Polyakov loop and the gluon condensation,which are proper order parameters to capture the deconfinement phase transition,also agree quantitatively well with the lattice QCD *** obtain a strong first-order confinement/deconfinement phase transition at Tc=276.5 Me V that is consistent with the lattice QCD *** on our model for a pure gluon hidden sector,we compute the stochastic gravitational waves and primordial black hole(PBH)productions from this confinement/deconfinement phase transition in the early *** resulting stochastic gravitational-wave backgrounds are found to be within detectability in the international Pulsar Timing Array and Square Kilometre Array in the near future when the associated productions of PBHs saturate the current observational bounds on the PBH abundances from the LIGO-Virgo-Collaboration O3 data.

关键词： AdS/QCD confinement/deconfinement phase transition gravitational wave primordial black hole

Is Yang-Mills theory unitary in fractional spacetime dimensions?

在线全文

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2024年第7期67卷 59-64页

作者： Qingjun Jin Ke Ren Gang Yang Rui Yu Graduate School of China Academy of Engineering physics Beijing 100193China School of physics and Astronomy Sun Yat-Sen UniversityZhuhai 519082China 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 SciencesHangzhou 310024China international Centre for theoretical physics Asia-Pacific Hangzhou 310024China School of Physical Science and Technology Inner Mongolia UniversityHohhot 010021China Beijing Computational Science Research center Beijing 100193China

We present concrete evidence that Yang-Mills theory exhibits non-unitarity in non-integer spacetime *** violation of unitarity stems from evanescent operators that,while vanishing in four dimensions,are non-zero in general d *** demonstrate that these evanescent operators lead to the emergence of both negative-norm states and complex anomalous dimensions.

关键词： gauge field theories field theories in dimensions other than four renormalization

Non-monotonic behavior of jam probability and stretchedexponential distribution in pedestrian counterflow

在线全文

学校读者我要写书评

暂无评论

Chinese physics B 2024年第9期33卷 259-266页

作者： Ze-Hao Chen Zhi-Xi Wu Jian-Yue Guan College of Physical Science and Technology Guangxi Normal UniversityGuilin 541004China Lanzhou center for theoretical physics Key Laboratory of Theoretical Physics of Gansu Provinceand Key Laboratory for Quantum Theory and Applications of the Ministry of EducationLanzhou UniversityLanzhou 730000China

We adopt a floor field cellular automata model to study the statistical properties of bidirectional pedestrian flow movingin a straight corridor. We introduce a game-theoretic framework to deal with the conflict of multiple pedestrians tryingto move to the same target location. By means of computer simulations, we show that the complementary cumulative distributionof the time interval between two consecutive pedestrians leaving the corridor can be fitted by a stretched exponentialdistribution, and surprisingly, the statistical properties of the two types of pedestrian flows are affected differently by theflow ratio, i.e., the ratio of the pedestrians walking toward different directions. We also find that the jam probability exhibitsa non-monotonic behavior with the flow ratio, where the worst performance arises at an intermediate flow ratio of around0.2. Our simulation results are consistent with some empirical observations, which suggest that the peculiar characteristicsof the pedestrians may attributed to the anticipation mechanism of collision avoidance.

关键词： traffic and crowd dynamics evolutionary game theory

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

在线全文

学校读者我要写书评

暂无评论

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 *** 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