A new parametric equation of state and quark stars  

作　　者：那学森 徐仁新 

机构地区：[1]School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University

出　　处：《Chinese Physics C》2011年第7期616-621,共6页中国物理C（英文版）

基　　金：Supported by China Scholarship Council, NSFC (10973002, 10935001);National Basic Research Program of China (2009CB824800);the John Templeton Foundation

摘　　要：It is still a matter of debate to understand the equation of state of cold matter with supra-nuclear density in compact stars because of unknown non-perturbative strong interaction between quarks. Nevertheless, it is speculated from an astrophysical view point that quark clusters could form in cold quark matter due to strong coupling at realistic baryon densities. Although it is hard to calculate this conjectured matter from first principles, one can expect that the inter-cluster interaction will share some general features with the nucleon- nucleon interaction successfully depicted by various models. We adopt a two-Gaussian component soft-core potential with these general features and show that quark clusters can form stable simple cubic crystal structure if we assume that the wave function of quark clusters have a Gaussian form. With this parametrization, the Tolman-Oppenheimer-Volkoff equation is solved with reasonably constrained parameter space to give massradius relations of crystalline solid quark stars. With baryon number densities truncated at 2n0 at surface and the range of the interaction fixed at 2 fm we can reproduce similar mass-radius relations to that obtained with bag model equations of state. The maximum mass ranges from - 0.5M⊙ to 〉 ～ 3M⊙. The recently measured high pulsar mass （〉～ 2M⊙） is then used to constrain the parameters of this simple interaction potential.It is still a matter of debate to understand the equation of state of cold matter with supra-nuclear density in compact stars because of unknown non-perturbative strong interaction between quarks. Nevertheless, it is speculated from an astrophysical view point that quark clusters could form in cold quark matter due to strong coupling at realistic baryon densities. Although it is hard to calculate this conjectured matter from first principles, one can expect that the inter-cluster interaction will share some general features with the nucleon- nucleon interaction successfully depicted by various models. We adopt a two-Gaussian component soft-core potential with these general features and show that quark clusters can form stable simple cubic crystal structure if we assume that the wave function of quark clusters have a Gaussian form. With this parametrization, the Tolman-Oppenheimer-Volkoff equation is solved with reasonably constrained parameter space to give massradius relations of crystalline solid quark stars. With baryon number densities truncated at 2n0 at surface and the range of the interaction fixed at 2 fm we can reproduce similar mass-radius relations to that obtained with bag model equations of state. The maximum mass ranges from - 0.5M⊙ to 〉 ～ 3M⊙. The recently measured high pulsar mass （〉～ 2M⊙） is then used to constrain the parameters of this simple interaction potential.

关 键 词：quark star solid quark matter mass radius relation massive pulsar 

分 类 号：P145.9[天文地球—天体物理]