共查询到20条相似文献,搜索用时 0 毫秒
1.
Xian-Feng Zhao 《International Journal of Theoretical Physics》2011,50(9):2951-2960
A new set of nucleon coupling constants (CZ11) is obtained for the relativistic mean field (RMF) theory based on the recent
experimental information on the symmetry energy derived from the data from NSCL/MSU. The surface gravitational redshift of
a proto neutron star (PNS) is examined within the RMF framework for the baryon octet system by using this set of parameters.
It is found that the surface gravitational redshift for CZ11 is smaller than that for GL97. For the CZ11 parameter set, the
surface gravitational redshift of a PNS at T=15 MeV is smaller than that at T=0 MeV. It is also found that the surface gravitational redshift corresponding to M
max/R for the CZ11 parameter set is smaller by about 10 percent than that for GL97, with M
max being the maximum mass and R being the corresponding radius. 相似文献
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Xian-Feng Zhao 《International Journal of Theoretical Physics》2017,56(10):3050-3060
The effect of mesons f 0(975) (named as f), ?(1020) (named as ?) and δ on the moment of inertia of the PNS PSR J0348+0432 is examined in the framework of the relativistic mean field theory considering the baryon octet. It is found that the energy density ε and pressure p will increase considering the mesons δ whereas will decrease as the mesons f and ? being considered. When the mesons f,? and δ are considered, the energy density and pressure will all decrease. It is also found that the contribution of mesons f, ? and δ to the central energy density is only the central energy density’s 0.06 ~0.6% whereas the contribution of mesons f, ? and δ to the central pressure is the central pressure’s 4 ~7%. For the radius, it will decrease when the contributions of mesons f, ? and δ are considered. The moment of inertia I will increase considering the mesons δ whereas will decrease as the mesons f and ? being considered. When the mesons f, ? and δ are all considered, the moment of inertia will decrease. It is found that the contribution of mesons f and ? to moment of inertia is 4 ~9 times larger than that of mesons δ. Our results show that the mesons f, ? and δ contribute to the moment of inertia’s 2 ~5%. 相似文献
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G. L. Comer 《Foundations of Physics》2002,32(12):1903-1942
Isolated neutron stars undergoing non-radial oscillations are expected to emit gravitational waves in the kilohertz frequency range. To date, radio astronomers have located about 1,300 pulsars, and can estimate that there are about 2×108 neutron stars in the galaxy. Many of these are surely old and cold enough that their interiors will contain matter in the superfluid or superconducting state. In fact, the so-called glitch phenomenon in pulsars (a sudden spin-up of the pulsar's crust) is best described by assuming the presence of superfluid neutrons and superconducting protons in the inner crusts and cores of the pulsars. Recently there has been much progress on modelling the dynamics of superfluid neutron stars in both the Newtonian and general relativistic regimes. We will discuss some of the main results of this recent work, perhaps the most important being that superfluidity should affect the gravitational waves from neutron stars (emitted, for instance, during a glitch) by modifying both the rotational properties of the background star and the modes of oscillation of the perturbed configuration. Finally, we present an analysis of the so-called zero-frequency subspace (i.e., the space of time-independent perturbations) and determine that it is spanned by two sets of polar (or spheroidal) and two sets of axial (or toroidal) degenerate perturbations for the general relativistic system. As in the Newtonian case, the polar perturbations are the g-modes which are missing from the pulsation spectrum of a non-rotating configuration, and the axial perturbations should lead to two sets of r-modes when the degeneracy of the frequencies is broken by having the background rotate. 相似文献
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Hyun Kyu Lee 《Physics of Particles and Nuclei Letters》2018,15(4):343-347
The possibility of assessing the equation of state of the neutron star matter using gravitational waves is briefly sketched. The effective theory recently proposed in the frame work of the scale-invariant hidden local symmetry is discussed to demonstrate its particular feature of a change over in EoS from lower density to higher density. The possible implications on the gravitational waves from coalescing binary neutron stars are discussed. 相似文献
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Neutron stars are known to show an accelerated spin-up of their rotational frequency on a short time scale of around 40 s, called a “glitch” in the neutron star. These neutron star glitches can emit short-duration transient gravitational wave signals as f-mode oscillations at frequencies between 1.5 and 3 kHz and damping times of less than a few seconds. The observed rate of neutron star glitches are currently limited by their electromagnetic observations. There could be a population of the isolated neutron stars in the galaxy for which there is no electromagnetic observation, but they can produce gravitational wave signals. Here, the sensitivity of the generic all-sky search for short-duration transients towards neutron star glitches during the Advanced LIGO and Virgo's third observing run using the Coherent WaveBurst algorithm is presented. The prospects of detecting signals from such glitching neutron stars for the upcoming fourth and fifth observing runs of Advanced LIGO and Virgo detectors are also described. 相似文献
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Quantum field theory in curved spacetime is used to show that gravitational redshift induces a unitary transformation on the quantum state of propagating photons. It is found that the transformation is a mode-mixing operation, and a protocol that exploits gravity to induce a Hong–Ou–Mandel-like interference effect on the state of two photons is devised. It is discussed how the results of this work can provide a demonstration of quantum field theory in curved spacetime. 相似文献
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For a given equation of state of neutron matter in the
relativistic σ-ω model, ๏๏๏๏๏
including the vacuum fluctuation of neutron and σ meson,
the properties of pure
neutron star are studied. We find that the maximum mass of pure neutron
star is ~ 2.0 M_{\odot}. At the same time, the influence of
incompressibility
of the nuclear matter to the properties of neutron star is
also studied. We also
find that the maximum mass of neutron stars decreases as equation of
state of neutron matter becomes softer. 相似文献
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We investigate the composition and structure of neutron-, hybrid-, and quark stars within an effective QCD-motivated model of strong interaction. The hadronic phase is described within a novel chiral SU(3) model and the deconfined quark-gluon plasma phase is formulated within the bag model. The phase transition between these phases is treated as a first order transition having two conserved charges. 相似文献
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How long do neutron star mountains last? The durability of elastically deformed crust is important for neutron star physics including pulsar glitches, emission of gravitational waves from static mountains, and flares from star quakes. The durability is defined by the strength properties of the Yukawa crystals of ions, which make up the crust. In this paper we extend our previous results [Mon. Not. R. Astron. Soc. 407 , L54 (2010)] and accurately describe the dependence of the durability on crust composition (which can be reduced to the dependence on the screening length λ of the Yukawa potential). We perform several molecular dynamics simulations of crust breaking and describe their results with a phenomenological model based on the kinetic theory of strength. We provide an analytical expression for the durability of neutron star crust matter for different densities, temperatures, stresses, and compositions. This expression can also be applied to estimate durability of Yukawa crystals in other systems, such as dusty plasmas in the laboratory (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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LIU Guang-Zhou LIU Wei ZHAO En-Guang 《理论物理通讯》2004,42(7)
In this paper a new phase structure of neutron star matter including nucleons and delta isobars is presented.Particle fractions populated and pion condensations in neutron star matter are investigated in this model. The existence of the pion condensations can postpone the appearance of delta isobars. We found that both the pion condensation and reduce of the ratio of delta isobar to nucleons couplings can soften the corresponding equation of state. The maximum masses and their corresponding radii of neutron stars are calculated, and the obtained values are in observational region. 相似文献
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中子星结构一直是核物理、粒子物理和天体物理共同关注的热点难题,双中子星并合事件GW170817的发现更是掀起这一研究的高潮。致密物质的状态方程是决定中子星结构的关键输入量,但是到目前为止,高密度的核物质状态方程行为依然很难确定。如今国内外已有许多运行或规划的大型核实验装置和天文观测设备,有望帮助我们很快解开致密物质状态方程的谜团。本文系统地阐述了基于微观多体理论和唯象模型对脉冲星类天体状态方程的研究现状,也讨论了奇异相变和奇异物质。结合理论计算和核物理实验及天文观测数据,致密物质状态方程的研究已取得相当多进展,但是也面临不少挑战,比如从实验和观测数据提取状态方程信息时的模型依赖,中子星各部分模型的不自洽以及各种依赖热密物质复杂动力学性质的实验和观测量。随着LIGO即将再运行而发现更多双中子星甚至中子星-黑洞等并合事件,多信使天文观测可望最终揭开中子星结构之谜。The matter state inside neutron stars (NSs) is an exciting problem in nuclear physics, particle physics and astrophysics. The equation of state (EOS) of NSs plays a crucial role in the present multimessenger astronomy, especially after the event of GW170817. Thanks to accruing studies with advanced telescopes and radioactive beam facilities, the unknown EOS of supranuclear matter could soon be understood. We review the current status of the EOS for pulsar-like compact objects, that have been studied with both microscopic many-body approaches and phenomenological models. The appearance of strange baryonic matter and strange quark matter are also discussed. We compare the theoretical predictions with different data coming from both nuclear physics experiments and astrophysical observations. Despite great progresses obtained in dense nuclear matter properties, there are various challenges ahead, such as the model dependence of the constraints extracted from either experimental or observational data, the lack of a consistent and rigorous many-body treatment of all parts of the star, the dependence of many observables on the turbulent dynamics of relevant hot dense system. As LIGO is about to run again and discover more NS merger events, multimessenger observations are expected to finally unravel the mystery of NS structure. 相似文献
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We analyze the correlations of the slope and curvature parameters of the symmetry energy with the neutron skin thickness of neutron-rich isotopes, and the crust-core transition density in neutron stars. The results are obtained within the microscopic Brueckner?CHartree?CFock approach, and are compared with those obtained with several Skyrme and relativistic mean field models. 相似文献