Holographic Derivation of Entanglement Entropy from AdS/CFT
Shinsei Ryu, Tadashi Takayanagi
TL;DR
Proposes a holographic prescription equating entanglement entropy in a d+1 CFT with the area of a d-dimensional minimal surface in AdS_{d+2}, S_A = Area(γ_A) / (4 G_N^{(d+2)}). The paper demonstrates exact agreement with the known 2D CFT result via AdS_3 geodesics and extends the construction to higher dimensions with belt and disk regions, including AdS_5×S^5. It also analyzes finite-temperature cases using AdS black holes, showing a thermal (horizon-wrapping) contribution that links entanglement entropy to the Bekenstein-Hawking entropy. Overall, this work provides a unified geometric framework for entanglement in holographic CFTs and clarifies how horizons encode entanglement structure.
Abstract
A holographic derivation of the entanglement entropy in quantum (conformal) field theories is proposed from AdS/CFT correspondence. We argue that the entanglement entropy in d+1 dimensional conformal field theories can be obtained from the area of d dimensional minimal surfaces in AdS_{d+2}, analogous to the Bekenstein-Hawking formula for black hole entropy. We show that our proposal perfectly reproduces the correct entanglement entropy in 2D CFT when applied to AdS_3. We also compare the entropy computed in AdS_5 \times S^5 with that of the free N=4 super Yang-Mills.
