# Evolution of Entanglement Entropy in Orbifold CFTs

## TL;DR

This paper investigates how the Renyi entanglement entropy evolves over time in orbifold conformal field theories, revealing universal behavior for rational radii and a novel double logarithmic scaling for non-rational cases.

## Contribution

It provides the first analysis of entanglement entropy dynamics in orbifold CFTs, identifying universal limits and a new scaling law in non-rational scenarios.

## Key findings

- Renyi entropy approaches a universal constant for rational radii.
- Discovered a $ ext{log} ext{log} ext{t}$ scaling law in non-rational orbifold CFTs.
- Characterized entanglement evolution in both cyclic and symmetric orbifold models.

## Abstract

In this work we study the time evolution of Renyi entanglement entropy for locally excited states created by twist operators in cyclic orbifold $(T^2)^n/\mathbb{Z}_n$ and symmetric orbifold $(T^2)^n/S_n$. We find that when the square of its compactification radius is rational, the second Renyi entropy approaches a universal constant equal to the logarithm of the quantum dimension of the twist operator. On the other hand, in the non-rational case, we find a new scaling law for the Renyi entropies given by the double logarithm of time $\log\log t$ for the cyclic orbifold CFT.