# WdW-patches in AdS$_{3}$ and complexity change under conformal transformations II

## TL;DR

This paper analyzes how the complexity of the CFT$_2$ ground state changes under small conformal transformations using the CA proposal, revealing new linear and logarithmic terms absent in the CV proposal.

## Contribution

It provides a detailed analysis of null-boundaries in WdW patches in AdS$_3$ and demonstrates the presence of linear and logarithmic terms in complexity change under conformal transformations in the CA framework.

## Key findings

- Complexity change includes linear and log terms in the infinitesimal parameter.
- Null-boundaries exhibit caustics and joint curves affecting the analysis.
- Results challenge certain field-theory duals of the CA proposal.

## Abstract

We study the null-boundaries of Wheeler-de Witt (WdW) patches in three dimensional Poincare-AdS, when the selected boundary timeslice is an arbitrary (non-constant) function, presenting some useful analytic statements about them. Special attention will be given to the piecewise smooth nature of the null-boundaries, due to the emergence of caustics and null-null joint curves. This is then applied, in the spirit of our previous paper arXiv:1806.08376, to the problem of how complexity of the CFT$_2$ groundstate changes under a small local conformal transformation according to the action (CA) proposal. In stark contrast to the volume (CV) proposal, where this change is only proportional to the second order in the infinitesimal expansion parameter $\sigma$, we show that in the CA case we obtain terms of order $\sigma$ and even $\sigma\log(\sigma)$. This has strong implications for the possible field-theory duals of the CA proposal, ruling out an entire class of them.