Seth Kurankyi Asante: Effective spin foam models for four dimensional quantum gravity

A number of approaches to four-dimensional quantum gravity, such as loop quantum gravity and holography, situate areas as their fundamental variables. These area variables are however, not free but satisfy certain constraints which allow for a consistent gluing. I will introduce a family of ‘effective’ spin foam models that incorporate a quantum area spectrum and impose gluing constraints as strongly as possible. The simplicity of these models allows to clarify some issues appearing in semi classical analysis of generic spin foam models. I will describe initial attempts toward testing quantum gravity equations on non-trivial spacetime boundaries. Numerical computations reveal a very rich structure of the amplitudes and a good semiclassical behaviour in a restricted regime of the parameter space.

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