标题： 度规仿射引力理论中非度规性的作用 显示英文标题

标题： The role of nonmetricity in metric-affine theories of gravity

摘要： 通过采用Palatini方法来处理引力的替代理论，即把仿射联络提升为独立变量的角色，这种引人入胜的选择包含了某些有趣（通常未被充分探索）的广义相对论推广理论的种子，即度规-仿射引力理论。这些理论的独特之处在于，它们提供了一种自然的方式，使物质场通过由联络本身构建的协变导数与独立联络耦合。借鉴有效场论的程序，我们研究了更高阶的度规-仿射引力理论的动力学，在完整版本中包括从曲率、非度规性和挠率构建的不变量。我们表明，即使将来自非度规性和挠性的二阶密度拉格朗日量项包括在内，联络仍然缺乏动力学，并作为辅助场可以通过代数方式消除，从而导致度规和物质场之间的一些额外相互作用。 显示英文摘要

摘要： The intriguing choice to treat alternative theories of gravity by means of the Palatini approach, namely elevating the affine connection to the role of independent variable, contains the seed of some interesting (usually under-explored) generalizations of General Relativity, the metric-affine theories of gravity. The peculiar aspect of these theories is to provide a natural way for matter fields to be coupled to the independent connection through the covariant derivative built from the connection itself. Adopting a procedure borrowed from the effective field theory prescriptions, we study the dynamics of metric-affine theories of increasing order, that in the complete version include invariants built from curvature, nonmetricity and torsion. We show that even including terms obtained from nonmetricity and torsion to the second order density Lagrangian, the connection lacks dynamics and acts as an auxiliary field that can be algebraically eliminated, resulting in some extra interactions between metric and matter fields.