Renxin Xu (徐仁新)

Professor; joint appointment with the Dept. of Astronomy
Research interests: 
particle astrophysics, pulsars, quark stars, neutron stars
Research Highlights: 

I am interested in compressed baryonic matter, such as pulsars especially, in astrophysics. Baryonic nuclei in the daily life are forbidden to fuse by compression due to the Coulomb repulse; nevertheless, it is usually unexpected in extraterrestrial extreme-environments: the gravity in a core of massive evolved star is so strong that all the other forces (including the Coulomb one) could be negligible. Compressed baryonic matter is then produced after supernova, manifesting itself as pulsar-like compact stars observed. The study of this compressed baryonic matter can not only be meaningful in fundamental physics (e.g., the elementary color interaction at low-energy scale, testing gravity theories, detecting nano-Hertz background gravitational waves), but has also profound implications in engineering applications (including time standard and navigation), and additionally, is focused by international as well as Chinese advanced facilities, either terrestrial or in space.

Historically, in 1930s, Lev Landau speculated that dense matter at supra-nuclear density in stellar cores could be considered as gigantic nuclei (the prototype of standard model of neutron star). However, we address that the residual compact object of supernova could be of condensed matter of quark clusters. We are both developing the quark-cluster star model and expecting to test it by observations.

 

我感兴趣于天文观测发现的压缩重子物质,特别是脉冲星。日常生活中的原子核是重子的典型代表,它们之间的Coulomb排斥有效地阻止其通过挤压物质而聚合起来。然而天体极端环境时常出人意料:大质量恒星演化至晚期时,其核心引力如此之强以至于其他任何力(当然包括Coulomb排斥)都难以媲美——压缩重子物质就这样在超新星爆发过程中诞生,并表现为观测到的脉冲星。对这类压缩重子物质的研究将不仅加深对强作用基本性质的认识, 而且有助于检验引力理论、探测低频引力波、建立精确的时间标准和导航体系,还是国际或国内在建或拟建大型天文望远镜的核心课题。

历史上Lev Landau曾推测恒星核心存在着巨大的原子核(可以看作“中子星'模型”的原型),其密度接近甚至超过原子核密度。然而我们的研究表明,脉冲星其实是由夸克集团而构成的凝聚体。未来我们将进一步完善夸克集团星模型,并期待各种观测检验。

Main Involvements: 

I am involved in the FAST early science research financially supported by National Basic Research Program of China, focusing on pulsar physics and observation.