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Imprints of ultralight axions on the gravitational wave and pulsar timing measurement

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Science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 23-29页

作者： Ning Xie Fa Peng Huang MOE Key Laboratory of TianQin Mission TianQin Research Center for Gravitational Physics&School of Physics and AstronomyFrontiers Science Center for TianQinGravitational Wave Research Center of CNSASun Yat-sen University(Zhuhai Campus)Zhuhai 519082China

The axion or axion-like particle motivated from a natural solution of strong CP problem or string theory is a promising dark matter candidate.We study the new observational effects of ultralight axion-like particles by the space-borne gravitational wave detector and the radio telescope.Taking the neutron star-black hole binary as an example,we demonstrate that the gravitational waveform could be obviously modified by the slow depletion of the axion cloud around the black hole formed through the superradiance process.We compare these new effects on the binary with the well-studied effects from dynamical friction with dark matter and dipole radiation in model-independent ways.Finally,we discuss the constraints from LIGO/Virgo and study the detectability of the ultralight axion particles at LISA and TianQin.

关键词： gravitational wave axion dark matter

Advancing space-based gravitational wave astronomy: Rapid parameter estimation via normalizing flows

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Science China(Physics,Mechanics & Astronomy) 2024年第3期67卷 20-33页

作者： Minghui Du Bo Liang He Wang Peng Xu Ziren Luo Yueliang Wu center for gravitational wave experiment National Microgravity LaboratoryInstitute of MechanicsChinese Academy of SciencesBeijing 100190China Key Laboratory of gravitational wave Precision Measurement of Zhejiang Province Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China Shanghai Institute of Optics and Fine Mechanics Chinese Academy of SciencesShanghai 201800China International Centre for Theoretical Physics Asia-Pacific University of Chinese Academy of SciencesBeijing 100049China Taiji Laboratory for gravitational wave Universe(Beijing/Hangzhou) University of Chinese Academy of SciencesBeijing 100049China Lanzhou center of Theoretical Physics Lanzhou UniversityLanzhou 730000China Hangzhou Institute for Advanced Study University of Chinese Academy of SciencesHangzhou 310024China Institute of Theoretical Physics Chinese Academy of SciencesBeijing 100190China

gravitational wave(GW) astronomy is witnessing a transformative shift from terrestrial to space-based detection, with missions like Taiji at the forefront. While the transition brings unprecedented opportunities for exploring massive black hole binaries(MBHBs), it also imposes complex challenges in data analysis, particularly in parameter estimation amidst confusion noise.Addressing this gap, we utilize scalable normalizing flow models to achieve rapid and accurate inference within the Taiji environment. Innovatively, our approach simplifies the data's complexity, employs a transformation mapping to overcome the year-period time-dependent response function, and unveils additional multimodality in the arrival time parameter. Our method estimates MBHBs several orders of magnitude faster than conventional techniques, maintaining high accuracy even in complex backgrounds. These findings significantly enhance the efficiency of GW data analysis, paving the way for rapid detection and alerting systems and enriching our ability to explore the universe through space-based GW observation.

关键词： Taiji program gravitational wave detection parameter estimation machine learning

Electrodynamics with violations of Lorentz and U(1)gauge symmetries and their Hamiltonian structures

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Chinese Physics C 2024年第6期48卷 45-57页

作者：杨秀鹏李瀑飞朱涛 Institute for Theoretical Physics and Cosmology Zhejiang University of TechnologyHangzhou 310032China United center for gravitational wave Physics(UCGWP) Zhejiang University of TechnologyHangzhou 310032China

This study aims to investigate Lorentz/U(1)gauge symmetry-breaking electrodynamics in the framework of the standard-model extension and analyze the Hamiltonian structure for the theory with a specific dimension of Lorentz breaking operators.For this purpose,we consider a general quadratic action of the modified electrodynamics with Lorentz/gauge-breaking operators and calculate the number of independent components of the operators at different dimensions in gauge invariance and breaking.With this general action,we then analyze how Lorentz/gauge symmetry-breaking can change the Hamiltonian structure of the theories by considering Lorentz/gauge-breaking operators with dimension as examples.We show that the Lorentz-breaking operators with gauge invariance do not change the classes of the theory constrains and the number of physical degrees of freedom of the standard Maxwell electrodynamics.When U(1)gauge symmetry-breaking operators are present,the theories generally lack a first-class constraint and have one additional physical degree of freedom compared to the standard Maxwell electrodynamics.

关键词： standard model extension electrodynamics Lorentz violations

Detection of astrophysical gravitational wave sources by TianQin and LISA

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 123-163页

作者： Alejandro Torres-Orjuela Shun-Jia Huang Zheng-Cheng Liang Shuai Liu Hai-Tian Wang Chang-Qing Ye Yi-Ming Hu Jianwei Mei MOE Key Laboratory of Tian Qin Mission Tian Qin Research Center for Gravitational PhysicsSchool of Physics and AstronomyFrontiers Science Center for Tian QinGravitational Wave Research Center of CNSASun Yat-Sen University(Zhuhai Campus)Zhuhai 519082China Department of Physics The University of Hong KongHong Kong 999077China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing100871China

TianQin and LISA are space-based laser interferometer gravitational wave(GW)detectors planned to be launched in the mid-2030s.Both detectors will detect low-frequency GWs around 10^(-2)Hz;however,Tian Qin is more sensitive to frequencies above this common sweet-spot while LISA is more sensitive to frequencies below 10^(-2)Hz.Therefore,Tian Qin and LISA will be able to detect the same sources but with different accuracy depending on the source and its parameters.We consider some of the most important astrophysical sources—massive black hole binaries,stellar-mass black hole binaries,double white dwarfs,extreme mass ratio inspirals,light and heavy intermediate mass ratio inspirals,as well as the stochastic gravitational background of astrophysical origin—that Tian Qin and LISA will be able to detect.For each of these sources,we analyze how far they can be detected(detection distance)and how well their parameters can be measured(detection accuracy)using a Fisher Matrix analysis.We compare the results obtained by the three detection scenarios(Tian Qin alone,LISA alone,and joint detection by LISA and Tian Qin)highlighting the gains from joint detection as well as the contribution of Tian Qin and LISA to a combined study of astrophysical sources.In particular,we consider the different orientations,lifetimes,and duty cycles of the two detectors to explore how they can give a more complete picture when working together.

关键词： wave extreme stochastic

General formalism for dirty extreme-mass-ratio inspirals

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 22-29页

作者： Ye Jiang Wen-Biao Han Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China Shanghai Frontiers Science center for gravitational wave Detection Shanghai 200240China

Detecting the environment around the supermassive black holes and tests of general relativity are important applications of extreme-mass-ratio inspirals(EMRIs).There is still a challenge to efficiently describe various“dirty”impacts on the inspirals,such as dark matter,gas,dipole radiation,and electromagnetic interaction.In this study,we find the inherent linearity of the asymptotic solution of the inhomogeneous Teukolsky equation.On the basis of this property,we completely decouple the factors of the perturber and the background spacetime in the energy fluxes and waveforms.With the new decoupling form,the waveforms of EMRIs with non-geodesic motion in Kerr spacetime can be conveniently calculated.This will help to resolve the environment(including gas,field,dark matter,electromagnetic interaction)around supermassive black holes and test general relativity.

关键词： gravitational wave Teukolsky equation extreme-mass-ratio inspirals

Learning topological defects formation with neural networks in a quantum phase transition

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Communications in Theoretical Physics 2024年第5期76卷 68-76页

作者： Han-Qing Shi Hai-Qing Zhang center for gravitational Physics Department of Space ScienceBeihang UniversityBeijing 100191China Peng Huanwu Collaborative center for Research and Education Beihang UniversityBeijing 100191China

Neural networks possess formidable representational power,rendering them invaluable in solving complex quantum many-body systems.While they excel at analyzing static solutions,nonequilibrium processes,including critical dynamics during a quantum phase transition,pose a greater challenge for neural networks.To address this,we utilize neural networks and machine learning algorithms to investigate time evolutions,universal statistics,and correlations of topological defects in a one-dimensional transverse-field quantum Ising model.Specifically,our analysis involves computing the energy of the system during a quantum phase transition following a linear quench of the transverse magnetic field strength.The excitation energies satisfy a power-law relation to the quench rate,indicating a proportional relationship between the excitation energy and the kink numbers.Moreover,we establish a universal power-law relationship between the first three cumulants of the kink numbers and the quench rate,indicating a binomial distribution of the kinks.Finally,the normalized kink-kink correlations are also investigated and it is found that the numerical values are consistent with the analytic formula.

关键词： neural networks machine learning transverse-field quantum Ising model kibble-zurek mechanism

Strong invariance principle for a counterbalanced random walk

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Applied Mathematics(A Journal of Chinese Universities) 2024年第2期39卷 370-380页

作者： TAN Hui-qun HU Zhi-shui DONG Liang International Institute of Finance School of ManagementUniversity of Science and Technology of ChinaHefei 230026China center for Basic Teaching and experiment Nanjing University of Science and TechnologyJiangyin 214443China

We study a counterbalanced random walkS_(n)=X_(1)+…+X_(n),which is a discrete time non-Markovian process andX_(n) are given recursively as follows.For n≥2,X_(n) is a new independent sample from some fixed law̸=0 with a fixed probability p,andX_(n)=−X_(v(n))with probability 1−p,where v(n)is a uniform random variable on{1;…;n−1}.We apply martingale method to obtain a strong invariance principle forS_(n).

关键词： random walk martingale invariance principle

Investigation on mechanical properties regulation of rock-like specimens based on 3D printing and similarity quantification

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International Journal of Mining Science and Technology 2024年第5期34卷 573-585页

作者： Duanyang Zhuang Zexu Ning Yunmin Chen Jinlong Li Qingdong Li Wenjie Xu center for Hypergravity experiment and Interdisciplinary Research Zhejiang University Hangzhou 310058 China MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering Zhejiang University

3D printing is widely adopted to quickly produce rock mass models with complex structures in batches,improving the consistency and repeatability of physical modeling. It is necessary to regulate the mechanical properties of 3D-printed specimens to make them proportionally similar to natural rocks. This study investigates mechanical properties of 3D-printed rock analogues prepared by furan resin-bonded silica sand particles. The mechanical property regulation of 3D-printed specimens is realized through quantifying its similarity to sandstone, so that analogous deformation characteristics and failure mode are acquired. Considering similarity conversion, uniaxial compressive strength, cohesion and stress–strain relationship curve of 3D-printed specimen are similar to those of sandstone. In the study ranges, the strength of 3D-printed specimen is positively correlated with the additive content, negatively correlated with the sand particle size, and first increases then decreases with the increase of curing temperature.The regulation scheme with optimal similarity quantification index, that is the sand type of 70/140,additive content of 2.5‰ and curing temperature of 81.6 ℃, is determined for preparing 3D-printed sandstone analogues and models. The effectiveness of mechanical property regulation is proved through uniaxial compression contrast tests. This study provides a reference for preparing rock-like specimens and engineering models using 3D printing technology.

关键词： 3D printing Mechanical property regulation Similarity quantification Rock analogue Sandstone

Nonexistence of quantum black and white hole horizons in an improved dynamic approach

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Science China(Physics,Mechanics & Astronomy) 2024年第8期Mechanics & Astronomy) .卷 60-77页

作者： Wen-Cong Gan Xiao-Mei Kuang Zhen-Hao Yang Yungui Gong Anzhong Wang Bin Wang College of Physics and Communication Electronics Jiangxi Normal University GCAP-CASPER Physics DepartmentBaylor University Institute for Theoretical Physics & Cosmology Zhejiang University of Technology United center for gravitational wave Physics(UCGWP) Zhejiang University of Technology center for Gravitation and Cosmology College of Physical Science and TechnologyYangzhou University Department of Physics School of Physical Science and TechnologyNingbo University School of Aeronautics and Astronautics Shanghai Jiao Tong University

In this paper, we study the quantum geometric effects near the locations where classical black hole horizons used to appear in Einstein's classical theory, within the framework of an improved dynamic approach, in which the internal region of a black hole is modeled by the Kantowski-Sachs(KS) spacetime and the two polymerization parameters are functions of the phase space variables. Our detailed analysis shows that the effects are so strong that black and white hole horizons of the effective quantum theory do not exist at all and instead are replaced by transition surfaces, across which the metric coefficients and their inverses are smooth and remain finite, as are the corresponding curvatures, including the Kretschmann scalar. These surfaces always separate trapped regions from anti-trapped regions. The number of such surfaces is infinite, so the corresponding KS spacetimes become geodesically complete, and no black and white hole-like structures exist in this scheme.

关键词： canonical quantization loop quantum gravity quantum aspects of black holes