Speaker
Description
During the last decade, a new and powerful paradigm has emerged in the context of quantum gravity, here understood as the still elusive quantum theory of gravitational degrees of freedom. This paradigm states that key features of quantum gravity are expected to display signatures of quantum chaos. Following such guiding principle, both compliance with random matrix theory in the long time limit and presence of fast scrambling in short times are now standard checks of any prospect system where quantum gravitational degrees of freedom may appear, either microscopically or as an effective description.
A particular type of abstract models inspired by string theory have gained much attention during the last years due to the possibility of having both a full-consistency quantum theory of gravity and a non-gravitational dual given by matrix models where quantum chaos signatures can be explicitly displayed and analyzed [1]. This models describe gravity in 1+1 dimensions, and the best studied example is the so-called Jackiw-Teitelboim model where 2-dimensional Einstein gravity is coupled with a dilation field.
In this talk I will approach the general idea of quantum gravity being quantum chaotic, but from the fresh perspective of semiclassical methods and periodic orbit theory where the starting point is the existence of a well-defined classical limit and a semiclassical regime and well known methods like the Gutzwiller trace formula and Wigner-Moyal expansions allow then to link quantum observables with classical structures [2]. The interesting aspect is, as I will try to explain, that in the context of quantum gravity neither the classical limit, nor the semiclassical regime and, in fact, not even the Hilbert space of the theory, are known!
[1] P. Saad, S. H. Shenker, D. Stanford, JT Gravity as Matrix Integral , arXiv:1903.11115
[2] F. Haneder, C.A. Moreno, T. Weber, J. D. Urbina, K. Richter, Beyond the ensemble paradigm in low dimensional quantum gravity: Schwarzian density, quantum chaos and wormhole contributions, arXiv:2410.02270. Phys. Rev. D 111 126015 (2025)
