本文選題：中子星 + 夸克物質(zhì)　； 參考：《華中師范大學(xué)》2012年博士論文

【摘要】：一般認為,脈沖星是由超密核物質(zhì)構(gòu)成的致密天體(中子星),但其內(nèi)部物質(zhì)成分到底如何至今仍在探索中。中子星理論模型與觀測對比研究是探究中子星內(nèi)部致密物質(zhì)性質(zhì)的重要手段,本文在第一章介紹了中子星內(nèi)部結(jié)構(gòu)及各種理論模型,并討論了各種觀測(最大質(zhì)量、表面熱輻射、質(zhì)量-半徑關(guān)系等)對理論模型的限制。 近年來一些研究結(jié)果表明,中子星內(nèi)極有可能存在奇異夸克物質(zhì)。隨著地面高能核物理的發(fā)展,高能重離子碰撞實驗也預(yù)示夸克物質(zhì)的存在,含有奇異夸克物質(zhì)的中子星理論模型研究顯得日益重要。本文第二章介紹了描述夸克物質(zhì)的主要狀態(tài)方程,重點研究了最新中子星最大質(zhì)量觀測結(jié)合奇異夸克物質(zhì)穩(wěn)定存在的物理條件,對奇異星內(nèi)夸克物質(zhì)狀態(tài)方程的限制,發(fā)現(xiàn)奇異星模型與觀測并不矛盾。對于密度依賴質(zhì)量模型描述的非色超導(dǎo)奇異星,最大質(zhì)量對參數(shù)C更為敏感,在參數(shù)允許范圍內(nèi),夸克星的最大質(zhì)量最大可達到2.25M& ,這一最大質(zhì)量可以解釋大質(zhì)量中子星的觀測值；而對于CFL奇異星,較大的s夸克質(zhì)量,需要更大的色超導(dǎo)能隙值,盡管可以通過提高能隙值而獲得更大的CFL奇異星質(zhì)量,但是s夸克質(zhì)量仍然在決定奇異星質(zhì)量中起到重要作用。與以往研究利用質(zhì)量-半徑關(guān)系對狀態(tài)方程進行排除不同,我們計算模擬了奇異星最大質(zhì)量隨兩個狀態(tài)方程參數(shù)連續(xù)變化的情況,給出了對狀態(tài)方程參數(shù)的明確限制。 表面熱輻射觀測是探尋中子星內(nèi)部物態(tài)及相關(guān)物理過程機制的另一重要途徑。隨著Chandara和XMM-Newton的升空,加之ROSAT巡天,中子星熱輻射觀測和研究有了顯著的進展。最新的來自XMM-Newton的觀測顯示,幾顆處于光子冷卻階段的年老(大于105年)中子星(PSR B2224+65,PSRJ2043-2740,PSR B0628-28,PSR B1929+10)出現(xiàn)老年高溫行為,而這些星體的解釋需要加熱機制的支持。本文在第三章介紹了中子星熱演化的基本理論,并對星體內(nèi)各種主要的加熱機制進行了對比分析,其中化學(xué)加熱機制是解釋老年中子星高溫行為最為重要的加熱機制。 化學(xué)加熱機制源于中子星轉(zhuǎn)動減慢過程中,星體內(nèi)各種弱作用反應(yīng)平衡的偏離。因為引發(fā)化學(xué)偏離的轉(zhuǎn)動時標要比恢復(fù)平衡的弱反應(yīng)時標快,系統(tǒng)始終處于非平衡狀態(tài),化學(xué)不平衡儲存的化學(xué)能通過反應(yīng)轉(zhuǎn)化為熱能加熱星體。第四章在介紹了中子星內(nèi)化學(xué)偏離及化學(xué)加熱機制發(fā)生的物理過程后,重點作了以下工作。 計算了非平衡態(tài)下色超導(dǎo)夸克物質(zhì)弱過程的反應(yīng)率和中微子輻射率。計算表明反應(yīng)同時受到化學(xué)偏離量和色超導(dǎo)的影響,有趣的是化學(xué)偏離會加快夸克物質(zhì)Urca過程反應(yīng)率提高中微子輻射率,而色超導(dǎo)因為壓縮了粒子的相空間而起到完全相反的作用。當化學(xué)偏離量較小時,色超導(dǎo)抑制了Urca過程的中微子反應(yīng)率,抑制的程度與色超導(dǎo)的能隙大小有關(guān),但是隨著化學(xué)偏離量的增大,當偏離量達到能隙大小附近時,抑制作用被快速完全破壞,反應(yīng)的中微子輻射率被大幅提升恢復(fù)至沒有色超導(dǎo)時的情況。計算結(jié)果對于研究含色超導(dǎo)夸克物質(zhì)的熱演化問題十分重要。 研究了中子星內(nèi)核子的退禁閉相變對化學(xué)偏離的重要影響,在均勻混雜星模型下計算化學(xué)偏離量和表面溫度演化情況,結(jié)果表明退禁閉相變加劇了中子星內(nèi)各粒子的化學(xué)偏離程度,并明顯提升化學(xué)加熱的加熱效率,加熱效應(yīng)更早出現(xiàn)。而且當星體內(nèi)的核子分別發(fā)生直接Urca過程和修改Urca過程時,混合相中夸克、核子對熱演化過程的主導(dǎo)地位并不相同�；瘜W(xué)加熱機制的研究提示我們,以往的研究主要考慮星體處于各種平衡態(tài),而實際上非平衡態(tài)才是旋轉(zhuǎn)中子星內(nèi)的常態(tài),非平衡態(tài)下中子星內(nèi)的物理圖象也與以往不同,可能出現(xiàn)一些新的物理現(xiàn)象和效應(yīng),這為我們以后的研究提供方向。
[Abstract]:It is generally believed that the pulsar is a compact celestial body (the neutron star) composed of superdense nuclei, but how the internal material composition is still exploring. The theoretical model of the neutron star and the observation and contrast study are the important means to explore the properties of the dense matter inside the neutron star. In the first chapter, the internal structure and various theories of the neutron star are introduced. Models, and the limitations of theoretical models on various observations (maximum mass, surface heat radiation, mass radius relations, etc.) are discussed.
In recent years, some research results show that there is a possible existence of singular quark matter in the neutron star. With the development of high energy nuclear physics on the ground, high energy heavy ion collision experiments also indicate the existence of quark matter. The theoretical model of neutron star containing singular quark matter is becoming more and more important. The second chapter introduces the main description of quark matter. For the state equation, we focus on the physical conditions of the maximum mass observation of the latest neutron star combined with the physical conditions of the singular quark matter, and the limitation of the state equation of the quark matter in the singular star. It is found that the singular star model is not contradictory to the observation. For the non chromatic superconducting singularity described by the density dependent mass model, the maximum mass to the parameter C is more. In the range of parameters, the maximum mass of the quark star can reach 2.25M&. This maximum mass can explain the observational value of the mass neutron star, and for the CFL singular star, the larger s quark mass requires a larger color superconducting gap value, although the mass of the CFL singularities can be obtained by raising the high energy gap value, but s The mass of quarks still plays an important role in determining the mass of singular stars. It is different from the previous study of the relationship between the mass radius and the equation of state. We calculate and simulate the continuous variation of the maximum mass of a singular star with the parameters of the two state equation, and give a definite limit to the parameter of the state.
The observation of surface thermal radiation is another important way to explore the internal state and related physical process mechanism of neutron stars. With the lift of Chandara and XMM-Newton and the ROSAT patrol, the observation and research of neutron star thermal radiation have made remarkable progress. The latest observations from XMM-Newton show that several years of aging in the phase of photon cooling (greater than 10) 5 years) the neutron stars (PSR B2224+65, PSRJ2043-2740, PSR B0628-28, PSR B1929+10) have high temperature behavior in the aged, and the explanation of these stars needs the support of the heating mechanism. In this paper, the basic theory of thermal evolution of neutron stars is introduced in the third chapter, and the main heating mechanisms in the stars are compared and analyzed, in which the mechanism of chemical heating is Explain the most important heating mechanism of the high temperature behavior of the neutron star in the old age.
The mechanism of chemical heating is due to the deviation of the equilibrium of various weak reactions in the star body during the rotation of the neutron star. Because the rotation time of the chemical deviation is faster than the weak reaction of the recovery equilibrium, the system is always in the nonequilibrium state and the chemical energy stored by chemical imbalance is converted into heat through the reaction to heat the star. The fourth chapter is After introducing the physical process of neutron star chemical deviation and the mechanism of chemical heating, the following work is emphasized.
The reaction rate and the neutrino emissivity of the weak process of the superconducting quark matter in the nonequilibrium state are calculated. The calculation shows that the reaction is influenced by the chemical deviation and the color superconductivity. It is interesting that the chemical deviation will accelerate the reaction rate of the quark matter Urca process to increase the neutrino radiant rate, and the color superconductor acts as the phase space of the particle. When the chemical deviation is small, color superconductivity inhibits the neutrino reaction rate in the Urca process, and the degree of inhibition is related to the energy gap size of the color superconductor, but with the increase of the chemical deviation, when the deviation reaches the gap size, the inhibition is rapidly completely destroyed and the neutrino radiation rate of the reaction is greatly raised. It is important to study the thermal evolution of color superconducting quark matter.
The important effect of the retrograde phase transition on the chemical deviation in the neutron star nucleus is studied. The chemical deviation and the surface temperature evolution are calculated under the uniform hybrid star model. The results show that the closed phase transition intensifies the chemical deviation of the particles in the neutron star, and obviously improves the heating efficiency of the chemical heating, and the heating effect appears earlier. In addition, when the nucleons in the body occur direct Urca process and modify the Urca process, the dominant position of the quarks and nucleons in the thermal evolution process is different in the mixed phase. The study of chemical heating mechanism suggests that the previous studies mainly consider the stars in various equilibrium states, but the nonequilibrium state is the constant in the rotating neutron star. The physical images of the neutron stars in the state and the nonequilibrium state are different from the previous ones, and some new physical phenomena and effects may appear, which provides the direction for our future research.
【學(xué)位授予單位】：華中師范大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2012
【分類號】：P145.6

【參考文獻】

相關(guān)期刊論文 前1條

1 喬國俊,徐仁新;X射線脈沖星的理論研究[J];北京大學(xué)學(xué)報(自然科學(xué)版);1998年05期

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本文編號：1933541