Quantum Universes on a computer - the CDT approach

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Quantum Universes on a computer
2020. 10. 09. 10:15
online (Teams)
Dániel Németh (Krakow)

Causal Dynamical Triangulations (CDT) is an attempt to quantize gravity via lattice regularization, where 4-dimensional tetrahedra play the role of the building blocks of space-time. The mathematical basis of CDT is a mixture of Regge calculus and Feynman path integral formulation. Numerical simulations show that CDT has a well defined semiclassical limit as the classical solution emerges in the form of the de-Sitter space-time. The Einstein-Hilbert action has a very simple form, with three bare coupling constants. The space of couplings reveals a rich phase structure of four phases with first and higher order phase transitions. In the recent years two different spatial boundary conditions were analyzed and no significant difference was found between sphere and torus. The most recent research is focused on implementing scalar fields, massive particles and applying RG methods. During my talk I will give a review about the current state of the field.