论文标题
在小组领域理论中迈向各向异性宇宙学
Towards anisotropic cosmology in group field theory
论文作者
论文摘要
在量子重力与无质量标量场的宇宙学组田地理论（GFT）模型中，总体体积被视为标量场的函数，遵循弗里德曼（Friedmann）的经典弗里德曼（Friedmann）动力学，平坦的弗里德曼 - 罗马·罗伯森 - 罗伯逊 - 罗伯森 - 沃尔克（FLRW）宇宙在低能范围内，同时在高爆发大力的范围内，在高爆发中，在高爆炸中均可在高爆发大力的境地。一个开放的问题是如何将这些结果推广到其他同质宇宙学。在这里，我们迈出的第一步是基于引入新的各向异性观察到的与$β$变量相似的新各向异性，以研究Misner的参数化中的新各向异性。在经典的Bianchi I时空中，$β$作为无质量标量场的表现，可以用作（引力）关系时钟。我们构建了一个GFT模型，该模型在扩展的宇宙$β$中最初像其经典类似物一样“衰减”，以显示先前研究的各向同性化。我们通过玩具模型中的分析近似值来支持GFT中的数值结果。我们工作的一个可能结果是对GFT中关系动态的定义不需要重要。
In cosmological group field theory (GFT) models for quantum gravity coupled to a massless scalar field the total volume, seen as a function of the scalar field, follows the classical Friedmann dynamics of a flat Friedmann-Lemaître-Robertson-Walker (FLRW) Universe at low energies while resolving the Big Bang singularity at high energies. An open question is how to generalise these results to other homogeneous cosmologies. Here we take the first steps towards studying anisotropic Bianchi models in GFT, based on the introduction of a new anisotropy observable analogous to the $β$ variables in Misner's parametrisation. In a classical Bianchi I spacetime, $β$ behaves as a massless scalar field and can be used as a (gravitational) relational clock. We construct a GFT model for which in an expanding Universe $β$ initially behaves like its classical analogue before "decaying" showing a previously studied isotropisation. We support numerical results in GFT by analytical approximations in a toy model. One possible outcome of our work is a definition of relational dynamics in GFT that does not require matter.
