Thermal states are vital: Entanglement Wedge Reconstruction from Operator-Pushing
Elliott Gesteau, Monica Jinwoo Kang
TL;DR
The paper develops an operator-pushing framework for bulk reconstruction in infinite-dimensional holographic settings by starting from a bulk $C^*$-algebra with a bulk-to-boundary isometry and a boundary $ ext{KMS}$ state $oldsymbol{\omega}$. Using GNS representations of the algebras, it constructs physically relevant Hilbert spaces and a bulk/boundary isometry $u$ that implement the bulk reconstruction, while proving conservation of Araki relative entropy and equality of modular flows between bulk and boundary. It thereby provides a state-dependent, algebraic realization of a wormhole’s other side, connecting ideas like the thermofield double and Papadodimas–Raju mirror operators, and applies the construction to an infinite-dimensional HaPPY code to realize a holographic wormhole with entanglement wedge reconstruction. The work blends algebraic quantum field theory tools (Tomita–Takesaki theory, Araki entropy) with holographic quantum error correction, highlighting the central role of thermal equilibrium via the $ ext{KMS}$ condition in enabling operator-level bulk reconstruction in the infinite-dimensional regime.
Abstract
We give a general construction of a setup that verifies bulk reconstruction, conservation of relative entropies, and equality of modular flows between the bulk and the boundary, for infinite-dimensional systems with operator-pushing. In our setup, a bulk-to-boundary map is defined at the level of the $C^*$-algebras of state-independent observables. We then show that if the boundary dynamics allow for the existence of a KMS state, physically relevant Hilbert spaces and von Neumann algebras can be constructed directly from our framework. Our construction should be seen as a state-dependent construction of the other side of a wormhole and clarifies the meaning of black hole reconstruction claims such as the Papadodimas-Raju proposal. As an illustration, we apply our result to construct a wormhole based on the HaPPY code, which satisfies all properties of entanglement wedge reconstruction.
