SISSA, Via Bonomea 265, 34136 Trieste, Italy.
Section of Astrophysics, Astronomy, and Mechanics, Department of Physics, University of Athens, Panepistimiopolis Zografos GR15783, Athens, Greece.
Phys Rev Lett. 2014 Mar 28;112(12):121101. doi: 10.1103/PhysRevLett.112.121101. Epub 2014 Mar 26.
Recently, it was shown that slowly rotating neutron stars exhibit an interesting correlation between their moment of inertia I, their quadrupole moment Q, and their tidal deformation Love number λ (the I-Love-Q relations), independently of the equation of state of the compact object. In the present Letter a similar, more general, universality is shown to hold true for all rotating neutron stars within general relativity; the first four multipole moments of the neutron star are related in a way independent of the nuclear matter equation of state we assume. By exploiting this relation, we can describe quite accurately the geometry around a neutron star with fewer parameters, even if we don't know precisely the equation of state. Furthermore, this universal behavior displayed by neutron stars could promote them to a more promising class of candidates (next to black holes) for testing theories of gravity.
最近的研究表明，缓慢自转的中子星在它们的转动惯量 I、四极矩 Q 和潮汐变形 Love 数 λ 之间存在有趣的关联（I-Love-Q 关系），这与致密星的物态方程无关。在本 Letter 中，我们表明，在广义相对论中，所有旋转的中子星都具有类似的、更普遍的通用性；在不考虑我们所假设的核物质物态方程的情况下，中子星的前四个多极矩以一种独立的方式相关联。通过利用这种关系，我们可以用更少的参数来准确地描述中子星周围的几何形状，即使我们不太清楚物态方程的确切情况。此外，这种中子星所表现出的普遍行为可能会促使它们成为比黑洞更有前途的一类候选体，用于检验引力理论。
