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Escape probability for isotropic emitters near Kerr black hole with astrometric

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Communications in Theoretical Physics 2024年第5期76卷 128-133页

作者： Yu-Xuan Han qing-Hua Zhu qing-guo huang CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesNo.19A Yuquan RoadBeijing 100049China Department of Physics Chongqing UniversityChongqing 401331China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced Study UCASHangzhou 310024China

The paper investigates the escape probability for isotropic emitters near a Kerr black *** propose a new approach to obtain the escape probability in a general manner,going beyond previous case-by-case *** approach is based on studies of the black hole shadow with astrometric observable and can be applied to emitters with an arbitrary 4-velocities and locations,even to the emitters outside of the equatorial *** also consider representative examples illustrating how escape probabilities vary with distance,velocity,and inclination ***,this new approach provides an effective method for studying escape probabilities near Kerr black holes.

关键词： Kerr black hole photon escape probability isotropic emitters

Cosmological interpretation for the stochastic signal in pulsar timing arrays

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Science China(Physics,Mechanics & Astronomy) 2024年第4期67卷 43-50页

作者： Yu-Mei Wu Zu-Cheng Chen qing-guo huang School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Department of Astronomy Beijing Normal UniversityBeijing 100875China Advanced Institute of Natural Sciences Beijing Normal UniversityZhuhai 519087China Department of Physics and Synergistic Innovation Center for Quantum Effects and Applications Hunan Normal UniversityChangsha 410081China CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China

The pulsar timing array(PTA)collaborations have recently reported compelling evidence for a stochastic signal consistent with a gravitational-wave *** this paper,we combine the latest data sets from NANOGrav,PPTA,and EPTA to explore cosmological interpretations for the PTA signal from first-order phase transitions,domain walls,and cosmic strings,*** find that the domain wall model is strongly disfavored with the Bayes factors compared with the first-order phase transitions and cosmic strings being 1/90 and 1/189,respectively,breaking the degeneracy among these models in individual data *** also find that:(1)a strong phase transition at temperatures below the electroweak scale is favored,and the bubble collisions make the dominant contribution to the energy density spectrum;(2)a small reconnection probability p<1.55×10^(-1)allowed by strings in(super)string theory is favored at the 95%confidence level,and ground-based detectors can further constrain the parameter space.

关键词： puslar timing arrays gravitational-wave background first-order phase transitions domain walls cosmic strings

Testing the first law of black hole mechanics with gravitational waves

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Science China(Physics,Mechanics & Astronomy) 2024年第10期67卷 76-82页

作者： Chao-Wan-Zhen Wang Jin-Bao Zhu guo-qing huang Fu-Wen Shu Department of Physics Nanchang UniversityNanchang 330031China Center for Relativistic Astrophysics and High Energy Physics Nanchang UniversityNanchang 330031China GCAP-CASPER Physics DepartmentBaylor UniversityWaco 76798-7316USA

The successful observation of gravitational waves has provided humanity with an additional method to explore the universe,particularly black *** this study,we utilize data from LIGO and Virgo gravitational wave observations to test the first law of black hole mechanics,employing two different *** consider the secondary compact object as a perturbation to the primary black hole before the merger,and the remnant black hole as a stationary black hole after the *** the pre-merger and post-merger analysis,our results demonstrate consistency with the first law,with an error level of approximate 25%at a68%credibility level for *** the full inspiral-merger-ringdown analysis,our results show consistency with the first law of black hole mechanics,with an error level of about 6%at a 68%credibility level and 10%at a 95%credibility level for ***,we observe that the higher the mass ratio of the gravitational wave source,the more consistent our results are with the first law of black hole ***,our study sheds light on the nature of compact binary coalescence and their implications for black hole mechanics.

关键词： gravitational waves black hole mechanics data analysis ringdown

Cosmological constraints on neutrino mass within consistent cosmological models

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Chinese Physics C 2024年第6期48卷 191-197页

作者：庞业煌张雪黄庆国 School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China Center for Gravitation and Cosmology College of Physical Science and TechnologyYangzhou UniversityYangzhou 225009China

Recently,the emergence of cosmological tension has raised doubts about the consistency of the ACDM *** constrain the neutrino mass within a consistent cosmological framework,we investigate three massive neutrinos with normal hierarchy(NH)and inverted hierarchy(IH)in both the axion-like early dark energy(AxiEDE)and AdS-EDE *** use joint datasets including the cosmic microwave background power spectrum from Plaanck 2018,Pantheon of type la supernova,baryon acoustic oscillation,and H0data from *** the vAxi-EDE model,we obtain∑m_(v),NH<0.152 eV and∑m_(v),IH<0.178 eV,whereas for the vAdS-EDE model,we find∑m_(v),NH<0.135 eV and∑m_(v),IH<0.167 *** results exhibit a preference for NH in both the vAxi-EDE and vAdS-EDE models.

关键词： neutrino mass cosmological tension early dark energy

Impacts of gravitational-wave background from supermassive black hole binaries on the detection of compact binaries by LISA

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Chinese Physics C 2024年第6期48卷 198-203页

作者：黄帆毕研晨曹周键黄庆国 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 Institute of Applied Mathematics Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China

In the frequency band of the Laser Interferometer Space Antenna(LISA),extensive research has been conducted on the impact of foreground confusion noise generated by galactic binaries within the Milky Way ***,recent evidence of a stochastic signal,announced by the NANOGrav,EPTA,PPTA,CPTA,and InPTA,indicates that the stochastic gravitational-wave background(SGWB)generated by supermassive black hole binaries(SMBHBs)can contribute strong background noise within the LISA *** the presence of such strong noise,it is expected to have significant impacts on LISA's scientific *** this study,we investigate the impacts of the SGWB generated by SMBHBs on the detection of individual massive black hole binaries,verified galactic binaries,and extreme mass ratio inspirals in the context of *** find it essential to resolve and eliminate the excess noise from the SGWB to guarantee the success of LISA's missions.

关键词： gravitational-wave background supermassive black hole binaries LISA

Measuring H0 from low-z datasets

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Science China(Physics,Mechanics & Astronomy) 2020年第9期63卷 2-6页

作者： Xue Zhang qing-guo huang 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 Center for Gravitation and Cosmology College of Physical Science and TechnologyYangzhou UniversityYangzhou 225009China Synergetic Innovation Center for Quantum Effects and Applications Hunan Normal UniversityChangsha 410081China

The Hubble constant H0 represents the expansion rate of the Universe at present and is closely related to the age of the *** accurate measurement of Hubble constant is crucial for modern ***,different cosmological observations give diverse values of Hubble constant in *** to now,there are two methods to measure the Hubble *** is to directly measure the Hubble constant based on distance ladder estimates of Cepheids and so *** other is to globally fit the Hubble constant under the assumption of a cosmological model,for example the "standard" ACDM *** the low-redshift observational datasets,including the Pantheon sample of Type Ⅰa supernovae,baryon acoustic oscillation measurements,and the tomographic Alcock-Paczynski method,we determine the Hubble constant to be 67.95-1.03+0.78,69.81-2.70+2.22 and66.75-4.23+3.42 km s^-1 Mpc^-1 at 68% confidence level in the △CDM,wCDM and W0Wa CDM models,*** to the Hubble constant given by Riess et *** 2019,we conclude that the new physics beyond the standard △CDM model is needed if all of these datasets are reliable.

关键词： Hubble constant dark energy equation of state

Inflation model selection revisited

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Science China(Physics,Mechanics & Astronomy) 2019年第12期62卷 28-33页

作者： Jun Li qing-guo huang 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

We update the constraints on the power spectra of primordial curvature perturbation and tensor perturbation including Planck data 2015(P15) and recently released BICEP2/Keck data(BK15), Baryon Acoustic Oscillation data and the Type Ia supernovae *** find that the upper limits of tensor-to-scalar ratio are 0.061, 0.064 and 0.072 at 95% confidence level(CL) in the ΛCDM+r,ΛCDM+r+αs and ΛCDM+r+αs+βs models respectively, where αsand βsare the running of scalar spectral index and running of running. The inflation model with a concave potential is favored at more than 95% CL. In addition, parametrizing the slow-roll parameter ε~ 1/N^p, where N is the e-folding number before the end of inflation and taken in the range of [50, 60] and [14, 75]respectively, we conclude that the inflation model with a monomial potential V(Ф) ~ Ф^n is disfavored at more than 95% CL, and both the Starobinsky inflation model and brane inflation model are still consistent with the data.

关键词： inflation cosmic microwave background (CMB) Baryon Acoustic Oscillation (BAO)

Non-tensorial gravitational wave background in NANOGrav 12.5-year data set

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Science China(Physics,Mechanics & Astronomy) 2021年第12期64卷 84-89页

作者： Zu-Cheng Chen Chen Yuan qing-guo huang 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 School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China Center for Gravitation and Cosmology College of Physical Science and TechnologyYangzhou UniversityYangzhou 225009China

We perform the first search for an isotropic non-tensorial gravitational-wave background(GWB) allowed in general metric theories of gravity in the North American Nanohertz Observatory for Gravitational Waves(NANOGrav) 12.5-year data set. By modeling the GWB as a power-law spectrum, we find strong Bayesian indication for a spatially correlated process with scalar transverse(ST) correlations whose Bayes factor versus the spatially uncorrelated common-spectrum process is 107 ± 7, but no statistically significant evidence for the tensor transverse, vector longitudinal, and scalar longitudinal polarization modes. The median and the 90% equal-tail amplitudes of ST mode are ■ , or equivalently the energy density parameter per logarithm frequency is ■, at frequency of 1/year.

关键词： gravitational wave scalar transverse polarization pulsar timing array

Detecting the neutrinos mass hierarchy from cosmological data

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Science China(Physics,Mechanics & Astronomy) 2018年第3期61卷 81-84页

作者： LiXin Xu qing-guo huang Institute of Theoretical Physics School of Physics Dalian University of Technology CAS Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences School of Physical Sciences University of Chinese Academy of Sciences

The neutrino oscillations imply that at least two neutrinos have non-zero masses[1].However,up to now,we only measure the differences of neutrino mass squares in a standard scenario with three massive eigenstates[2],i.e.

关键词：中微子数据检测宇宙论非零