混合星质量半径关系的研究

发布时间：2018-06-22 10:04

本文选题：混合星 + 状态方程　；参考：《华中师范大学》2014年硕士论文

【摘要】：致密星是恒星演化末期的最终形态,中子星便是其中的一种致密星,它是研究极端物理条件下高密核物质物理的“天然实验室”,也是低温物理的“实验室”,对高密核物质的特性和致密星体热演化等问题的研究有着非常重要的意义。然而,由于核物理理论的不确定性,中子星核心部分的物质组成及状态方程(EOS)仍是人们讨论的热点。中子星的内部有很多可能物态形式,如纯夸克物质、纯核子物质、核子与夸克混合的物质、色超导等。本文主要讨论核子与夸克混合的情况,即混合星。我们首先详细讨论了混合星的强子相、夸克相的状态方程,研究了不同强子相的介子组成和不同夸克相参数对星体的状态方程的影响。这里的强子相选用平均场近似(RMF)的方法,分别考虑σ与ω相互作用的情况和σ自相互作用的情况,其对应的参数分别选用SVI-1(scalar-vector interaction)和NL3(nonlinear)。结果显示,SVI-1参数模型和NL3参数模型相比,对状态方程有软化作用。而夸克相选用场关联方法(FCM),可以观察到胶子凝聚值(G2)和静态夸克反夸克势(V1)对状态方程的影响。在相变过程中,我们介绍了麦克斯韦(Maxwell)和吉布斯(Gibbs)两种构造理论,并给出了相变过程中压强随粒子数密度变化的关系。接着,我们介绍了TOV (Tolman, Oppenheimer, Volkoff)方程来描述中子星的质量半径(M-R)关系,结合混合星内部的状态方程,对混合星M-R关系的结果作了四层分析：第一,我们给定G2在相同的强子相参数模型和相变构造理论下观察V1对M-R关系的影响。结果显示,最大质量随着V1的增加而增加,但V1很小时的变化不明显。第二,我们给定V1在相同的强子相参数模型和相变构造理论下观察G2对M-R关系的影响。结果显示,最大质量随着G2的增加而增加。第三,在这个条件下,我们改变强子相的参数模型,在不同的G2下进行比较。结果显示,SVI-1参数模型得到的最大质量基本上比NL3的结果要小,但在G2=0.006GeV4时出现反转,这也表示混合星M-R的关系受强子相和夸克相共同影响。第四,我们在相同条件下,比较两种相变构造理论对M-R的影响,发现,Gibbs构造理论得到的曲线更加平滑。
[Abstract]:The dense star is the final form in the late stage of stellar evolution, and the neutron star is one of the dense stars. It is a "natural laboratory" for studying the physics of high-density nuclear matter under extreme physical conditions, and a "laboratory" for low-temperature physics. It is of great significance to study the characteristics of dense nuclear matter and the thermal evolution of dense stars. However, due to the uncertainty of nuclear physics theory, the matter composition and equation of state (EOS) of the neutron star core are still a hot topic. There are many possible state forms in neutron stars, such as pure quark matter, pure nuclear matter, nucleon and quark mixed matter, color superconducting and so on. This paper mainly discusses the mixing of nucleons and quarks, that is, mixed stars. We first discuss the state equations of hadrons and quarks of mixed stars in detail, and study the effects of meson composition of different hadrons and quark phase parameters on the equation of state of stars. The hadronic phase uses the mean field approximation (RMF) method. The interaction between 蟽 and 蠅 and 蟽 self-interaction are considered respectively. The corresponding parameters are SVI-1 (scalar-vector interaction) and NL3 (nonlinear)., respectively. The results show that the SVI-1 parameter model softens the equation of state compared with the NL3 parameter model. The effect of gluon coacervation (G2) and static quark antiquark potential (V1) on the equation of state can be observed by using the field correlation method (FCM). In the process of phase transition, we introduce Maxwell and Gibbs structural theory, and give the relation between pressure and population density. Then, we introduce TOV (Tolman, Oppenheimer, Volkoff) equation to describe the mass radius (M-R) relation of neutron star. Combining with the equation of state inside the mixed star, we analyze the results of M-R relation of mixed star in four layers. The effect of V1 on the M-R relation is observed under the same Hadron phase parameter model and phase transition construction theory. The results show that the maximum mass increases with the increase of V1, but the change of V1 is not obvious. Secondly, under the same Hadron phase parameter model and phase transition construction theory, we give the influence of G2 on M-R relationship. The results showed that the maximum mass increased with the increase of G2. Thirdly, under this condition, we change the parameter model of Hadron phase and compare it with different G2. The results show that the maximum mass obtained by the SVI-1 parameter model is basically smaller than that obtained by NL3, but the inversion occurs at G22.006GeV4, which also indicates that the relationship between the mixed star M-R is affected by the Hadron phase and the quark phase. Fourthly, under the same conditions, we compare the influence of two phase transformation structures on M-R, and find that the curves obtained by the Gibbs construction theory are smoother.
【学位授予单位】：华中师范大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P145.6

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