Week 13.05.2024 – 19.05.2024

I will review the theoretical and experimental status in the search of primordial non-Gaussianity, focussing on some recent developments and ideas. In particular I will try to answer the question: what are we going to learn when experiments will be able to probe f_NL ~ 1?

In this talk, I will employ an ADM deparametrization strategy to discuss the radial canonical formalism of asymptotically AdS_3 gravity. It leads to the identification of a radial 'time' before quantization, namely the volume time, which is canonically conjugate to York time. Holographically, this allows to interpret the semi-classical partition function of TTbar theory as a Schrodinger wavefunctional satisfying a Schrodinger evolution equation in volume time. The canonical perspective can be used to construct from the Hamilton-Jacobi equation the BTZ solution, and corresponding semi-classical Wheeler-DeWitt states. Based on upcoming work with Matthew J. Blacker, Blanca Hergueta and Sirui Ning.

For matrix models and QFT, we discuss how holographic emergent geometry appears from matrix degrees of freedom (specifically, adjoint scalars in super Yang-Mills theory) and how operator algebra that describes an arbitrary region of the bulk geometry can be constructed. We pay attention to the subtle difference between the notions of wave packets that describe low-energy excitations: QFT wave packet associated with the spatial dimensions of QFT, matrix wave packet associated with the emergent dimensions from matrix degrees of freedom, and bulk wave packet which is a combination of QFT and matrix wave packets. In QFT, there is an intriguing interplay between QFT wave packet and matrix wave packet that connects quantum entanglement and emergent geometry. We propose that the bulk wave packet is the physical object in QFT that describes the emergent geometry from entanglement. This proposal sets a unified view on two seemingly different mechanisms of holographic emergent geometry: one based on matrix eigenvalues and the other based on quantum entanglement. Further intuition comes from the similarity to traversable wormholes.