This is a complete and exhaustive review on the so-called holographic axion model—a bottom-up holographic system characterized by the presence of a set of shift symmetric scalar bulk fields whose profiles are taken to be linear in the spatial coordinates. This simple model implements the breaking of translational invariance of the dual field theory by retaining the homogeneity of the background geometry and therefore allowing for controllable and fast computations. The usages of this model are very vast and they are a proof of the spectacular versatility of the framework. In this review, we touch upon all the up-to-date aspects of this model from its connection with massive gravity and effective field theories, to its role in modeling momentum dissipation and elastic properties ending with all the phenomenological features and its hydrodynamic description. In summary, this is a complete guide to one of the most used models in Applied Holography and a must-read for any researcher entering this field.

这是对所谓的全息轴子模型（一种自下而上的全息系统）的完整而详尽的评论，其特征在于存在一组偏移对称标量体场，其轮廓在空间坐标中被视为线性。这个简单的模型通过保持背景几何的均匀性来打破双场理论的平移不变性，从而实现可控和快速的计算。该模型的用途非常广泛，它们证明了该框架具有惊人的多功能性。在这篇评论中，我们从该模型与大重力和有效场理论的联系中触及了该模型的所有最新方面，其在模拟动量耗散和弹性特性中的作用，以所有现象学特征及其流体动力学描述结束。总而言之，这是应用全息学中最常用模型之一的完整指南，并且是进入该领域的任何研究人员的必读之书。