标题： 中子星的相对论潮汐特性 显示英文标题

标题： Relativistic tidal properties of neutron stars

摘要： 我们研究中子星对外部相对论潮汐场的各种线性响应。 We focus on three different tidal responses, associated to three different tidal coefficients: (i) a gravito-electric-type coefficient G\mu _\ell =[length]^{2\ell +1} measuring the \ell ^{th}-order mass multipolar moment GM_{a_1... a_\ell } induced in a star by an external \ell ^{th}-order gravito-electric tidal field G_{a_1... a_\ell }; (ii) a gravito-magnetic-type coefficient G\sigma _\ell =[length]^{2\ell +1} measuring the \ell ^{th} spin multipole moment G S_{a_1... a_\ell } induced in a star by an external \ell ^{th}-order gravito-magnetic tidal field H_{a_1... a_\ell }; and (iii) a dimensionless ``shape'' Love number h_\ell measuring the distortion of the shape of the surface of a star by an external \ell ^{th}-order gravito-electric tidal field. 所有无量纲潮汐系数 G\mu _\ell /R^{2\ell +1}, G\sigma _\l /R^{2\ell +1}和 h_\ell （其中 R 是恒星的半径）都被发现对恒星的“紧凑度” c\equiv GM/(c_0^2 R) 的值有很强的敏感性（其中我们用 c_0 表示光速）。 特别是，G\mu _\l /R^{2\l +1}\sim k_\ell 被发现随着c的增加而显著减小，当c被形式上扩展到“黑洞（BH）极限”c^{BH}=1/2时，其值降至零。 形状的Love数h_\ell 也发现随着c的增加而显著减小，尽管在c\to c^{BH}的形式极限中并未消失。 \mu 乘以\ell 以及\sigma 乘以\ell 在 c\to 乘以 c^{BH}时的正式消失是黑洞无毛性质的结果；这表明，但并未证明，描述黑洞引力相互作用的有效作用可能不需要通过非最小世界线耦合来增强。 显示英文摘要

摘要： We study the various linear responses of neutron stars to external relativistic tidal fields. We focus on three different tidal responses, associated to three different tidal coefficients: (i) a gravito-electric-type coefficient G\mu_\ell=[length]^{2\ell+1} measuring the \ell^{th}-order mass multipolar moment GM_{a_1... a_\ell} induced in a star by an external \ell^{th}-order gravito-electric tidal field G_{a_1... a_\ell}; (ii) a gravito-magnetic-type coefficient G\sigma_\ell=[length]^{2\ell+1} measuring the \ell^{th} spin multipole moment G S_{a_1... a_\ell} induced in a star by an external \ell^{th}-order gravito-magnetic tidal field H_{a_1... a_\ell}; and (iii) a dimensionless ``shape'' Love number h_\ell measuring the distortion of the shape of the surface of a star by an external \ell^{th}-order gravito-electric tidal field. All the dimensionless tidal coefficients G\mu_\ell/R^{2\ell+1}, G\sigma_\l/R^{2\ell+1} and h_\ell (where R is the radius of the star) are found to have a strong sensitivity to the value of the star's ``compactness'' c\equiv GM/(c_0^2 R) (where we indicate by c_0 the speed of light). In particular, G\mu_\l/R^{2\l+1}\sim k_\ell is found to strongly decrease, as c increases, down to a zero value as c is formally extended to the ``black-hole (BH) limit'' c^{BH}=1/2. The shape Love number h_\ell is also found to significantly decrease as c increases, though it does not vanish in the formal limit c\to c^{BH}. The formal vanishing of \mu_\ell and \sigma_\ell as c\to c^{BH} is a consequence of the no-hair properties of black holes; this suggests, but in no way proves, that the effective action describing the gravitational interactions of black holes may not need to be augmented by nonminimal worldline couplings.