## Abstract

We consider the computation of volumes contained in a spatial slice of AdS_{3} in terms of observables in a dual CFT. Our main tool is kinematic space, defined either from the bulk perspective as the space of oriented bulk geodesics, or from the CFT perspective as the space of entangling intervals. We give an explicit formula for the volume of a general region in a spatial slice of AdS_{3} as an integral over kinematic space. For the region lying below a geodesic, we show how to write this volume purely in terms of entangling entropies in the dual CFT. This expression is perhaps most interesting in light of the complexity = volume proposal, which posits that complexity of holographic quantum states is computed by bulk volumes. An extension of this idea proposes that the holographic subregion complexity of an interval, defined as the volume under its Ryu-Takayanagi surface, is a measure of the complexity of the corresponding reduced density matrix. If this is true, our results give an explicit relationship between entanglement and subregion complexity in CFT, at least in the vacuum. We further extend many of our results to conical defect and BTZ black hole geometries.

Original language | English |
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Article number | 12 |

Journal | Journal of High Energy Physics |

Volume | 2019 |

Issue number | 1 |

DOIs | |

State | Published - 1 Jan 2019 |

Externally published | Yes |

## Keywords

- AdS-CFT Correspondence
- Black Holes in String Theory
- Gauge-gravity correspondence

## ASJC Scopus subject areas

- Nuclear and High Energy Physics