DataSheet1_Quantum Fluctuations in the Effective Relational GFT Cosmology.pdf

We analyze the size and evolution of quantum fluctuations of cosmologically relevant geometric observables, in the context of the effective relational cosmological dynamics of GFT models of quantum gravity. We consider the fluctuations of the matter clock observables, to test the validity of the relational evolution picture itself. Next, we compute quantum fluctuations of the universe volume and of other operators characterizing its evolution (number operator for the fundamental GFT quanta, effective Hamiltonian and scalar field momentum). In particular, we focus on the late (clock) time regime, where the dynamics is compatible with a flat FRW universe, and on the very early phase near the quantum bounce produced by the fundamental quantum gravity dynamics.

我们针对量子引力的群场论（Group Field Theory, GFT）模型的有效关系宇宙学动力学框架，分析了与宇宙学相关的几何可观测量的量子涨落的规模及其演化规律。我们通过考察物质钟可观测量的涨落，来验证关系演化图景本身的合理性。随后，我们计算了宇宙体积以及其他表征宇宙演化的算符的量子涨落——其中包括基础群场论量子的数算符、有效哈密顿量与标量场动量。具体而言，我们重点聚焦于两类演化时域：一是与平直弗里德曼-罗伯逊-沃尔克（Friedmann-Robertson-Walker, FRW）宇宙动力学兼容的晚期（钟）时域，二是由基础量子引力动力学所催生的量子反弹附近的极早期相位。