Speaker
Description
Abstract:
The gravitational path integral requires summing over geometries, yet it remains unclear which configurations should be included and which principles should constrain this sum. In particular, the role of causal structure and topology change remains subtle, especially in Lorentzian quantum gravity where amplitudes are intrinsically complex and highly constrained.
In this talk, I will discuss how these questions can be addressed within simplicial approaches to gravity, where geometry is discretized and causal relations can be implemented explicitly. I will review how Lorentzian Regge calculus and related discrete models provide a controlled setting to study causal structure, singular configurations, and their contribution to the path integral.
Special emphasis will be placed on configurations with localized causal irregularities, such as conical singularities and point-like defects, and on their relation to spatial topology-change. I will illustrate how such configurations contribute to Lorentzian amplitudes and how they differ from their Euclidean counterparts using low-dimensional examples. I will conclude with their implications for Lorentzian approaches to quantum gravity and open questions for future work.
| Keyword-1 | path-integral |
|---|---|
| Keyword-2 | lorentzian |
| Keyword-3 | causal struture |