# An Infalling Observer in AdS/CFT

**Authors:** Kyriakos Papadodimas, Suvrat Raju  
**arXiv:** [1211.6767](https://arxiv.org/abs/1211.6767)  
**Date:** 2012-11-28  
**Summary page:** https://www.summarizepaper.com/en/paper/1211.6767v1/

## Key points

- Authors Papadodimas and Raju study an observer falling into a black hole using AdS/CFT correspondence
- Focus on reconstructing local bulk operators measured by the observer outside the black hole
- Feasibility demonstrated due to effective doubling of observables in boundary theory, especially in pure states close to thermal state
- New perspective offered on information loss and metric structure at black hole horizon
- Proposal that accurate identification of black-hole microstates requires measurements with accuracy of e^{-S_{BH}}
- Challenge to existing fuzzball model representing pure states with macroscopically distinct geometries
- Description of black hole interior using CFT operators provides insights into complementarity and preserves unitarity without firewalls
- Innovative approach sheds light on fundamental aspects of black hole physics and explores quantum gravity within AdS/CFT correspondence

## Summary

In their paper "An Infalling Observer in AdS/CFT," authors Kyriakos Papadodimas and Suvrat Raju explore the experience of an observer falling into a black hole using the AdS/CFT correspondence. The study focuses on reconstructing the local bulk operators that are measured by the observer along their trajectory outside the black hole. The authors demonstrate that this is feasible due to an effective doubling of observables in the boundary theory, particularly when it is in a pure state close to the thermal state. By leveraging this framework, Papadodimas and Raju offer a new perspective on questions surrounding information loss and the metric structure at the black hole horizon. They propose that for an observer to accurately identify black-hole microstates, measurements would need to be conducted with an accuracy of e^{-S_{BH}}, challenging existing proposals like the fuzzball model. This model suggests that pure states are represented by macroscopically distinct geometries. However, Papadodimas and Raju's description of the black hole interior using CFT operators not only provides insights into black hole complementarity but also offers a method for preserving unitarity without resorting to firewalls. This innovative approach sheds light on fundamental aspects of black hole physics and opens up new avenues for exploring quantum gravity within the context of AdS/CFT correspondence.