# A World without Pythons would be so Simple

### APA

Engelhardt, N. (2021). A World without Pythons would be so Simple. Perimeter Institute. https://pirsa.org/21040024

### MLA

Engelhardt, Netta. A World without Pythons would be so Simple. Perimeter Institute, Apr. 12, 2021, https://pirsa.org/21040024

### BibTex

@misc{ pirsa_PIRSA:21040024, doi = {10.48660/21040024}, url = {https://pirsa.org/21040024}, author = {Engelhardt, Netta}, keywords = {Quantum Fields and Strings}, language = {en}, title = {A World without Pythons would be so Simple}, publisher = {Perimeter Institute}, year = {2021}, month = {apr}, note = {PIRSA:21040024 see, \url{https://pirsa.org}} }

Netta Engelhardt Massachusetts Institute of Technology (MIT)

**Collection**

**Talk Type**Scientific Series

**Subject**

## Abstract

We show that bulk operators lying between the outermost extremal surface and the asymptotic boundary admit a simple boundary reconstruction in the classical limit. This is the converse of the Python's lunch conjecture, which proposes that operators with support between the minimal and outermost (quantum) extremal surfaces - e.g. the interior Hawking partners - are highly complex. Our procedure for reconstructing this "simple wedge" is based on the HKLL construction, but uses causal bulk propagation of perturbed boundary conditions on Lorentzian timefolds to expand the causal wedge as far as the outermost extremal surface. As a corollary, we establish the Simple Entropy proposal for the holographic dual of the area of a marginally trapped surface as well as a similar holographic dual for the outermost extremal surface. We find that the simple wedge is dual to a particular coarse-grained CFT state, obtained via averaging over all possible Python's lunches. An efficient quantum circuit converts this coarse-grained state into a "simple state" that is indistinguishable in finite time from a state with a local modular Hamiltonian. Under certain circumstances, the simple state modular Hamiltonian generates an exactly local flow; we interpret this result as a holographic dual of black hole uniqueness.