Holographic Complexity for disentangled states
Tokiro Numasawa
TL;DR
This work probes holographic complexity in AdS/BCFT setups with end-of-the-world branes by examining the maximal volume $C_V$ and the Wheeler-DeWitt action $C_A$ for BTZ-like geometries. It shows that when the horizon size $r_H$ approaches the cutoff $r_0$ (or the ETW brane contacts the cutoff), holographic entanglement entropy $S_A$ vanishes and the volume $C_V$ similarly tends to zero, signaling a product-state reference in the CV picture. In contrast, the CA results depend on the chosen WdW regularization: Regularization 1 yields $C_A o 0$ in the entangled-to-disentangled limit, while Regularization 2 generally produces nonvanishing or divergent $C_A$ with tension-dependent terms, revealing subtleties in defining holographic complexity for BCFTs. The analysis emphasizes the pivotal roles of ETW-brane tension, boundary entropy, and regularization in interpreting holographic complexity and points to future work on time dependence and quantum corrections in these setups.
Abstract
In this paper we consider the maximal volume and the action, which are conjectured to be gravity duals of the complexity, in the black hole geometries with end of the world branes. These geometries are duals of boundary states in CFTs which have small real space entanglement. When we raise the black hole temperature while keeping the cutoff radius, black hole horizons or end of the world branes come in contact with the cutoff surface. In this limit, holographic entanglement entropy reduces to 0. We studied the behavior of the volume and the action. We found that the volume reduces to 0 in this limit. The behavior of the action depends on their regularization. We study the implication of these results to the reference state of the holographic complexity both in the complexity = volume or the complexity = action conjectures.
