时间：12月16日（周一）下午15:00-16:00

地点：勤园20-518

Abstract:

I will introduce the ongoing numerical progress in covariant Loop Quantum Gravity (LQG). I have developed a comprehensive algorithm and a Mathematica program to construct boundary data and compute real and complex critical points in spinfoam amplitudes. This approach covers both spacelike tetrahedra and triangles in the EPRL model and timelike tetrahedra and triangles in the Conrady-Hnybida extension, aiming at addressing a wide range of physical scenarios such as cosmology and black holes. The numerical method can be applied to study homogeneous and isotropic quantum cosmology using the spinfoam formalism. In this study, I define a coupling of a scalar field to the 4-dimensional Lorentzian Engle-Pereira-Rovelli-Livine (EPRL) spinfoam model and employ the numerical method of complex critical points to investigate the model on two different simplicial complexes: the triangulations of a single hypercube and two connected hypercubes. The results have nontrivial implications for effective cosmological dynamics.

Introduction:

Dongxue Qu has been a postdoctoral researcher at the Perimeter Institute for Theoretical Physics in Canada since 2022. She earned her doctorate from Florida Atlantic University in the United States in 2022, specializing in numerical methods in Quantum Gravity. She obtained her bachelor’s degree from Beijing Jiaotong University in 2014 and her master’s degree from the same university in 2017.