High Energy Theory Seminar

In this talk, I will give an answer to the question “which QFT states holographically describe the emergence of semiclassical (conformal) geometry?” via a new construct in QFT: the causal density matrix. This new construct relies on the “lightcone cut” approach to spacetime emergence, and generalizes it to arbitrary QFTs (that may or may not have holographic duals). In the presence of a semiclassical spacetime, lightcone cuts explain both the emergence of holographic dimensions and the way in which geometry is encoded in a holographic dual. Properties of the causal density matrix indicate that some features of quantum error correction are more general than AdS/CFT. Within AdS/CFT, I will argue that the “reduced” causal density matrix is dual to the causal wedge.