标题： 新颖的精确超紧凑和超稀疏带毛黑洞，来源于常规和幻影标量场 显示英文标题

标题： Novel exact ultra-compact and ultra-sparse hairy black holes emanating from regular and phantom scalar fields

摘要： 在包含一个与引力最小耦合的标量场的简单引力理论框架中，我们研究了具有非平凡标量毛发的次级类型解析黑洞解的出现。 尽管使用我们的设置可以获得渐近（A）dS解，但在当前工作的背景下，我们仅关注渐近平坦的解。 首先，我们研究了来自常规标量场和幻影标量场的静态和球对称黑洞解的性质。 我们发现，由常规标量场引起的解是描述超紧凑黑洞的解，而幻影标量场则产生超稀疏黑洞解。 后者是可能具有非常低密度的黑洞，因为与超紧凑黑洞相反，它们的视界半径始终大于相同质量对应的施瓦茨希尔德黑洞的视界半径。 然后，我们将上述静态解推广到缓慢旋转的情况，并显式计算了它们的角速度。 最后，对所得到的解的轴向扰动进行了研究，在此我们表明，在我们理论的自由参数的参数空间中总是存在一个区域，允许同时存在超紧凑和超稀疏黑洞。 显示英文摘要

摘要： In the framework of a simple gravitational theory that contains a scalar field minimally coupled to gravity, we investigate the emergence of analytic black-hole solutions with non-trivial scalar hair of secondary type. Although it is possible for one to obtain asymptotically (A)dS solutions using our setup, in the context of the present work, we are solely interested in asymptotically flat solutions. At first, we study the properties of static and spherically symmetric black-hole solutions emanating from both regular and phantom scalar fields. We find that the regular-scalar-field-induced solutions are solutions describing ultra-compact black holes, while the phantom scalar fields generate ultra-sparse black-hole solutions. The latter are black holes that can be potentially of very low density since, contrary to ultra-compact ones, their horizon radius is always greater than the horizon radius of the corresponding Schwarzschild black hole of the same mass. Then, we generalize the above static solutions to slowly rotating ones and compute their angular velocities explicitly. Finally, the study of the axial perturbations of the derived solutions takes place, in which we show that there is always a region in the parameter space of the free parameters of our theory that allows the existence of both ultra-compact and ultra-sparse black holes.