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Strange star candidates revised within a quark model with chiral mass scaling

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Research in astronomy and Astrophysics 2011年第4期11卷 482-490页

作者： Ang Li Guang-Xiong Peng Ju-Fu Lu department of physics and institute of theoretical physics and Astrophysics Xiamen University Xiamen 361005 China department of physics Graduate University Chinese Academy of Sciences Beijing 100049 China

We calculate the properties of static strange stars using a quark model with chiral mass scaling. The results are characterized by a large maximum mass （-1.6 M⊙） and radius （-10km）. Together with a broad collection of modern neutron star models, we discuss some recent astrophysical observational data that could shed new light on the possible presence of strange quark matter in compact stars. We conclude that none of the present astrophysical observations can prove or confute the existence of strange stars.

关键词： dense matter -- elementary particles -- equation of state -- stars: inte-riors

Probing primordial gravitational waves: Ali CMB Polarization Telescope

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National Science Review 2019年第1期6卷 145-154页

作者： Hong Li Si-Yu Li Yang Liu Yong-Ping Li Yifu Cai Mingzhe Li Gong-Bo Zhao Cong-Zhan Liu Zheng-Wei Li He Xu Di Wu Yong-Jie Zhang Zu-Hui Fan Yong-Qiang Yao Chao-Lin Kuo Fang-Jun Lu Xinmin Zhang Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences theoretical physics Division Institute of High Energy PhysicsChinese Academy of Sciences University of Chinese Academy of Sciences CAS Key Laboratory for Researches in Galaxies and Cosmology Department of AstronomyUniversity of Scienceand Technology of China Interdisciplinary Center for theoretical Study University of Science and Technology of China National Astronomical Observatories Chinese Academy of Sciences institute of Cosmology& Gravitation University of Portsmouth Key Laboratory of Particle Astrophysics Institute of High EnergyPhysics Chinese Academy of Sciences Key Laboratory of Particle Astrophysics Institute of High Energy Physics ChineseAcademy of Sciences department of astronomy School of Physics Peking University physics department Stanford University

In this paper, we will give a general introduction to the Ali CMB Polarization Telescope(Ali CPT) project,which is a Sino–US joint project led by the institute of High Energy physics and involves many different institutes in China. It is the first ground-based Cosmic Microwave Background(CMB) polarization experiment in China and an integral part of China’s Gravitational-wave Program. The main scientific goal of the Ali CPT project is to probe the primordial gravitational waves(PGWs) originating from the very early Universe. The AliCPT project includes two stages. The first stage, referred to as AliCPT-1, is to build a telescope in the Ali region of Tibet at an altitude of 5250 meters. Once completed, it will be the highest ground-based CMB observatory in the world and will open a new window for probing PGWs in the northern hemisphere. The AliCPT-1 telescope is designed to have about 7000 transition-edge sensor detectors at 95 GHz and 150 GHz. The second stage is to have a more sensitive telescope(Ali CPT-2) with more than 20 000 detectors. Our simulations show that AliCPT will improve the current constraint on the tensor-to-scalar ratio r by one order of magnitude with three years’ observation. Besides the PGWs, Ali CPT will also enable a precise measurement of the CMB rotation angle and provide a precise test of the CPT symmetry. We show that three years’ observation will improve the current limit by two orders of magnitude.

关键词： primordial gravitational waves cosmic microwave background Ali CMB Polarization Telescope

Coherent Control of the Goos–Hnchen Shifts in a Four-Level N Type Atomic Medium

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Communications in theoretical physics 2014年第12期61卷 864-870页

作者： Parisa Maboodi Soheila Hemmatzadeh Seyyed Hossein Asadpour H.Rahimpour Soleimani Research institute for Applied physics and astronomy University of Tabriz Tabriz Iran department of physics University of Guilan Rasht Iran

The behavior of the Goos–H¨anchen(GH) shifts of the reflected and transmitted probe light beams is theoretically investigated. In a fixed geometrical configuration, the effect of quantum interference induced by spontaneous emission on the phase control of the GH shifts is analyzed in this paper. It is found that in a four-level N-type atomic system as an intracavity medium, the GH shifts of the reflected and transmitted probe light beam are completely phase dependent.

关键词： Goos–Hnchen shift quantum interference group index

Footprints of axion-like particle in pulsar timing array data and James Webb Space Telescope observations

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Science China(physics,Mechanics & astronomy) 2024年第11期67卷 55-62页

作者： Shu-Yuan Guo Maxim Khlopov Xuewen Liu Lei Wu Yongcheng Wu Bin Zhu department of physics Yantai UniversityYantai 264005 China institute of physics Southern Federal UniversityRostov on Don 344090 Russia National Research Nuclear University MEPhI(Moscow Engineering physics institute) Moscow 115409 Russia Virtual institute of Astroparticle physics Paris 75018 France department of physics and institute of theoretical physics Nanjing Normal UniversityNanjing 210023 China

Several pulsar timing array(PTA) collaborations have recently reported the evidence for a stochastic gravitational-wave background(SGWB), which can unveil the formation of primordial seeds of inhomogeneities in the early universe. With the SGWB parameters inferred from PTAs data, we can make a prediction of the seeds for early galaxy formation from the domain walls in the axion-like particles(ALPs) field distribution. This also naturally provides a solution to the observation of high redshifts by the James Webb Space Telescope. The predicted photon coupling of the ALP is within the reach of future experimental searches.

关键词： stochastic gravitational-wave background pulsar timing array axion-like particle JWST

Stochastic ravitational wave background from PBH-ABH mergers

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Chinese physics C 2022年第5期46卷 180-188页

作者： Wenfeng Cui Fei Huang Jing Shu Yue Zhao CAS Key Laboratory of theoretical physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China department of physics and astronomy University of CaliforniaIrvineCA 92697USA School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China CAS Center for Excellence in Particle physics Beijing 100049China Center for High Energy physics Peking UniversityBeijing 100871China School of Fundamental physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China International Centre for theoretical physics Asia-Pacific Beijing/HangzhouChina department of physics and astronomy University of UtahSalt Lake CityUT 84112USA

The measurement of gravitational waves produced by binary black-hole mergers at the Advanced LIGO has encouraged extensive studies on the stochastic gravitational wave background. Recent studies have focused on gravitational wave sources made of the same species, such as mergers from binary primordial black holes or those from binary astrophysical black holes. In this paper, we study a new possibility - the stochastic gravitational wave background produced by mergers of one primordial black hole and one astrophysical black hole. Such systems are necessarily present if primordial black holes exist. We study the isotropic gravitational wave background produced through the history of the universe. We find it is very challenging to detect such a signal. We also demonstrate that it is improper to treat the gravitational waves produced by such binaries in the Milky Way as a directional stochastic background due to a very low binary formation rate.

关键词： gravitational wave primordial black hole astro black hole merger stochastic gravitational wave background

Quasilocal Energy for Static Charged Black Holes in String Theory

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Communications in theoretical physics 2001年第7期36卷 125-128页

作者： WANG Shi-Liang JING Ji-Liang WANG Yong-Jiu institute of physics and physics department Hunan Normal University Changsha 410081 China Institute of Physics and Physics Department Hunan Normal University Changsha 410081 China Department of Astronomy and Applied Physics University of Science and Technology of China Hefei 230026 China Institute of Physics and Physics Department Hunan Normal University Changsha 410081 China

The Brown-York quasilocal energies of some static charged dilaton black holes are calculated, and then the validity of Martinez's conjecture is explored in string theory. It is shown that the energy is positive and monotonically decreases to the ADM mass at spatial infinity, and the conjecture that the Brown-York quasilocal energy at the outer horizon of black hole reduces to twice of its irreducible mass is still applicable for the static charged black holes in string theory. The result is different from Bose-Naing's one.

关键词： quasilocal energy, black hole, string theory

(2+1)-Dimensional AdS Black Hole in Grand Canonical Ensemble

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Communications in theoretical physics 2001年第10期36卷 413-416页

作者： CHEN Ju-Hua JING Ji-Liang WANG YongJiu department of physics Institute of Physics Hunan Normal University Changsha 410081 China Department of Physics Institute of Physics Hunan Normal University Changsha 410081 China Department of Astronomy and Applied Physics University of Science and Technology of China Hefei 230026 China Department of Physics Institute of Physics Hunan Normal University Changsha 410081 China

We investigate thermodynamics of the (2+1)-dimensional AdS black hole in grand canonical ensemble. In the York's formalism, the black hole is enclosed in a "box" with a finite radius and the boundary temperature, radius and potential are fixed in the grand canonical ensemble. We investigate the thermodynamical properties such as action,entropy, temperature, etc. We only find the stable solution for (2+1)-dimensional AdS black hole and do not find the instanton with the negative heat capacity.

关键词： action, grand canonical ensemble, (2+1)-dimensional AdS black hole

The gravitational-wave physics

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National Science Review 2017年第5期4卷 687-706页

作者： Rong-Gen Cai Zhoujian Cao Zong-Kuan Guo Shao-Jiang Wang Tao Yang CAS Key Laboratory of theoretical physics Institute of Theoretical PhysicsChinese Academy of Sciences School of astronomy and Space Science University of Chinese Academy of Sciences department of astronomy Beijing Normal University School of Physical Sciences University of Chinese Academy of Sciences institute of Applied Mathematics Academy of Mathematics and Systems ScienceChinese Academy of Sciences

The direct detection of gravitational wave by Laser Interferometer Gravitational-Wave Observatory indicates the coming of the era of gravitational-wave astronomy and gravitational-wave cosmology. It is expected that more and more gravitational-wave events will be detected by currently existing and planned gravitational-wave detectors. The gravitational waves open a new window to explore the Universe and various mysteries will be disclosed through the gravitational-wave detection, combined with other cosmological probes. The gravitational-wave physics is not only related to gravitation theory, but also is closely tied to fundamental physics, cosmology and astrophysics. In this review article, three kinds of sources of gravitational waves and relevant physics will be discussed, namely gravitational waves produced during the inflation and preheating phases of the Universe, the gravitational waves produced during the first-order phase transition as the Universe cools down and the gravitational waves from the three phases:inspiral, merger and ringdown of a compact binary system, respectively. We will also discuss the gravitational waves as a standard siren to explore the evolution of the Universe.

关键词： gravitational waves inflation reheating first order phase transition binary black holes standard siren

Fast adaptive flat-histogram ensemble to enhance the sampling in large systems

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Science China(physics,Mechanics & astronomy) 2015年第9期58卷 5-10页

作者： XU Shun ZHOU Xin JIANG Yi WANG YanTing School of Physical Sciences University of Chinese Academy of Sciences department of Mathematics and Statistics Georgia State University State Key Laboratory of theoretical physics Institute of Theoretical PhysicsChinese Academy of Sciences

An efficient novel algorithm was developed to estimate the Density of States(DOS) for large systems by calculating the ensemble means of an extensive physical variable, such as the potential energy, U, in generalized canonical ensembles to interpolate the interior reverse temperature curve β_s(U)=SU/U, where S(U) is the logarithm of the DOS. This curve is computed with different accuracies in different energy regions to capture the dependence of the reverse temperature on U without setting prior grid in the U space. By combining with a U-compression transformation, we decrease the computational complexity from O(N3/2) in the normal Wang Landau type method to O(N1/2) in the current algorithm, as the degrees of freedom of system N. The efficiency of the algorithm is demonstrated by applying to Lennard Jones fluids with various N, along with its ability to find different macroscopic states, including metastable states.

关键词： molecular dynamics simulations enhanced sampling density of states generalized canonical ensemble flat-histogram ensemble