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New results on the dynamics of critical collapse

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Chinese Physics C 2024年第6期48卷 204-210页

作者：郭俊起胡宇王盼盼邵成刚 School of Physics and Technology University of JinanJinan 250022China MOE Key Laboratory of Fundamental Physical Quantities Measurement Hubei Key Laboratory of Gravitation and Quantum PhysicsPGMFand School of PhysicsHuazhong University of Science and TechnologyWuhan 430074China

We study the dynamics of the critical collapse of a spherically symmetric scalar *** analytic expressions for the metric functions and matter field in the large-radius region are *** the central region,owing to the bo... 详细信息

关键词： critical collapse spacetime singularities numerical relativity

Energy in critical collapse

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Communications in Theoretical Physics 2023年第12期75卷 97-104页

作者： Yu Hu Jun-Qi Guo Junbin Li Cheng-Gang Shao Hongsheng Zhang MOE Key Laboratory of Fundamental Physical Quantities Measurement Hubei Key Laboratory of Gravitation and Quantum PhysicsPGMFand School of PhysicsHuazhong University of Science and TechnologyWuhan 430074HubeiChina School of Physics and Technology University of JinanJinan 250022ShandongChina Department of Mathematics Sun Yat-sen UniversityGuangzhou 510275GuangdongChina

We study the energy issue in critical *** is found that in critical collapse,the contribution from the material energy is greater than that from the gravitational *** quantity m/r plays an important role in identifying the formation of an apparent horizon in gravitational collapse,where m is the Misner-Sharp mass and r is the areal *** observe that in critical collapse,the maximum value of m/r fluctuates between 2/15 and 4/*** denotes a large gap between critical collapse and black hole formation for which the criterion is m/r=1/2.

关键词： quasi-local energy critical collapse numerical relativity

IMEX Evolution of Scalar Fields on Curved Backgrounds

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Communications in Computational Physics 2009年第10期6卷 1063-1094页

作者： S.R.Lau H.P.Pfeiffer J.S.Hesthaven Division of Applied Mathematics Brown UniversityProvidenceRI 02912USA Theoretical Astrophysics and relativity Group 130-33 California Institute of TechnologyPasadenaCA 91125USA Also at the Department of Mathematics and Statistics University of New MexicoAlbuquerqueNM 87131USA.

Inspiral of binary black holes occurs over a time-scale of many orbits,far longer than the dynamical time-scale of the individual black *** evolutions of a binary system therefore require excessively many time-steps to capture interesting *** present a strategy to overcome the Courant-Friedrichs-Lewy condition in such evolutions,one relying on modern implicit-explicit ODE solvers and multidomain spectral methods for elliptic *** analysis considers the model problem of a forced scalar field propagating on a generic curved ***,we encounter and address a number of issues pertinent to the binary black hole problem in full general *** to the Schwarzschild geometry in KerrSchild coordinates,we document the results of several numerical experiments testing our strategy.

关键词： Implicit-explicit schemes spectral methods numerical relativity black holes

The Gravitational-wave physics Ⅱ: Progress

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Science China(Physics,Mechanics & Astronomy) 2021年第12期64卷 18-67页

作者： Ligong Bian Rong-Gen Cai Shuo Cao Zhoujian Cao He Gao Zong-Kuan Guo Kejia Lee Di Li Jing Liu Youjun Lu Shi Pi Jian-Min Wang Shao-Jiang Wang Yan Wang Tao Yang Xing-Yu Yang Shenghua Yu Xin Zhang CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China Department of Astronomy Beijing Normal UniversityBeijing 100875China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100080China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China School of Astronomy and Space Sciences University of Chinese Academy of SciencesBeijing 100049China Key Laboratory for Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced Study(HIAS)University of Chinese Academy of SciencesHangzhou 310024China MOE Key Laboratory of Fundamental Physical Quantities Measurements Hubei Key Laboratory of Gravitation and Quantum PhysicsNational Precise Gravity Measurement Facility(PGMF)Department of Astronomy and School of PhysicsHuazhong University of Science and TechnologyWuhan 430074China Asia Pacific Center for Theoretical Physics Pohang 37673Korea Department of Physics College of SciencesNortheastern UniversityShenyang 110819China Key Laboratory of Data Analytics and Optimization for Smart Industry(Northeastern University) Ministry of EducationShenyang 110819China Department of Physics Chongqing UniversityChongqing 401331China

It has been a half-decade since the first direct detection of gravitational waves, which signifies the coming of the era of the gravitational-wave astronomy and gravitational-wave cosmology. The increasing number of the detected gravitational-wave events has revealed the promising capability of constraining various aspects of cosmology, astronomy, and gravity. Due to the limited space in this review article, we will briefly summarize the recent progress over the past five years, but with a special focus on some of our own work for the Key Project "Physics associated with the gravitational waves" supported by the National Natural Science Foundation of China. In particular,(1) we have presented the mechanism of the gravitational-wave production during some physical processes of the early Universe, such as inflation, preheating and phase transition, and the cosmological implications of gravitational-wave measurements;(2) we have put constraints on the neutron star maximum mass according to GW170817 observations;(3) we have developed a numerical relativity algorithm based on the finite element method and a waveform model for the binary black hole coalescence along an eccentric orbit.

关键词： gravitational wave gravitational-wave cosmology gravitational-wave astronomy numerical relativity

Evidence for False Vacuum States inside the Cores of Massive Pulsars and the Ramification on the Measurements of Their True Masses

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Journal of Modern Physics 2023年第11期14卷 1409-1425页

作者： Ahmad A. Hujeirat Mauritz M. Wicker IWR University of Heidelberg Heidelberg Germany

Based on the theory and observations of glitching pulsars, we show that the ultra-cold supranuclear dense matter inside the cores of massive pulsars should condensate in vacua, as predicated by non-perturbative QCD. The trapped matter here forms false vacuums embedded in flat spacetimes and completely disconnected from the outside world. Although the vacuum expectation value here vanishes, the masses and sizes of these incompressible superfluid cores are set to grow with cosmic times, in accord with the Onsager-Feynman superfluidity analysis. We apply our scenario to several well-studied pulsars, namely the Crab, Vela, PSR J0740+6620 and find that the trapped mass-contents in their cores read {0.15,0.55,0.64}, implying that their true masses are {1.55,2.35,2.72} , respectively. Based thereon, we conclude that: 1) The true masses of massive pulsars and neutron stars are much higher than detected by direct observations and, therefore, are unbounded from above, 2) The remnant of the merger event in GW170817 should be a massive NS harbouring a core with 1.66 .

关键词： numerical relativity Pulsars Magnetars Neutrons Stars Black Holes Quantum Vacuum QCD Condensed Matter Incompressibility Superfluidity Super-Conductivity