标题： Proca星的非球形基态 显示英文标题

标题： The non-spherical ground state of Proca stars

摘要： 球形Proca星（PSs）被视为PSs家族中的基态。 相应地，球形PSs被认为具有稳定解的基本分支。 在本信中，我们提供了能量、形态和动态的证据，表明球形PSs实际上是激发态。 基态被证明是一族静态的、非球形的，实际上为长形的PSs。 基本分支中的球形星体，尽管在球形扰动下是稳定的，但最终会屈服于非球形动力学，发生对称性破缺，转变为长形PSs。 我们还提供了长形PSs的动力学形成的证据，从球形稀疏初始数据开始，通过引力冷却形成。 因此，PSs提供了一个显著的例子（可能是紧凑的）相对论星体，在广义相对论中与一个简单、物理的场论模型最小耦合的情况下，静态性加上稳定性意味着非球形性。 显示英文摘要

摘要： Spherical Proca Stars (PSs) are regarded as the ground state amongst the family of PSs. In accordance, spherical PSs are thought to have a fundamental branch of stable solutions. In this Letter, we provide energetic, morphological and dynamical evidence that spherical PSs are actually excited states. The ground state is shown to be a family of static, non-spherical, in fact prolate, PSs. The spherical stars in the fundamental branch, albeit stable against spherical perturbations, turn out to succumb to non-spherical dynamics, undergoing an isometry breaking into prolate PSs. We also provide evidence for the dynamical formation of prolate PSs, starting from spherical dilute initial data, via gravitational cooling. Consequently, PSs provide a remarkable example of (possibly compact) relativistic stars, in General Relativity minimally coupled to a simple, physical, field theory model, where staticity plus stability implies non-sphericity.