Oct 16 – 17, 2025
Perimeter Institute for Theoretical Physics
America/Toronto timezone

Entropies for gravitational systems from simplicial Lorentzian path integrals

Oct 16, 2025, 2:00 PM
20m
PI/3-394 - Skyroom (Perimeter Institute for Theoretical Physics)

PI/3-394 - Skyroom

Perimeter Institute for Theoretical Physics

60
Contributed Talk

Speaker

José de Jesús Padua Argüelles (Perimeter Institute for Theoretical Physics)

Description

Recent advances have argued how gravitational entropies can be computed directly from Lorentzian path integrals, avoiding the problems of Euclidean methods associated with the conformal factor problem that makes a path integral over Euclidean geometries manifestly ill defined. In particular, the de Sitter horizon entropy can be recovered from a real-time path integral that computes the dimension of the Hilbert space associated with a spatial ball. Similarly, the swap entropy of an evaporating black hole (central to the replica paradigm resolution of the black hole information paradox) can be computed in this way. Quantum Regge Calculus, a lattice-like approach to quantum gravity, enables concrete realizations of these scenarios, providing insights beyond continuum methods. This perspective clarifies aspects of gravitational path integrals and may have implications for approaches such as causal dynamical triangulations and spin foams, where Regge-like formulations play a fundamental role.

Author

José de Jesús Padua Argüelles (Perimeter Institute for Theoretical Physics)

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