# Entanglement Negativity Transitions in Chaotic Eigenstates

## TL;DR

This paper extends the understanding of entanglement negativity transitions in chaotic eigenstates, revealing enhanced corrections near phase transitions and connecting gravitational calculations with permutation sums, including for Re9nyi entropies.

## Contribution

It generalizes previous entanglement entropy results to entanglement negativity, deriving permutation sums and analyzing their implications for gravitational and quantum information measures.

## Key findings

- Derived permutation sums for negativity spectrum
- Reproduced gravitational results for certain quantities
- Identified tension with partially transposed entropy calculations

## Abstract

It was recently noted that the entanglement entropy for a subsystem of a chaotic eigenstate exhibits an enhanced correction when the subsystem approaches a phase transition at half the total system size. This enhanced correction was derived for general subsystems by Dong and Wang by summing over noncrossing permutations, which can be thought of as ``saddles'' either in a sum emerging from averaging over Wick contractions or in an analogous gravitational calculation. We extend these results to the case of entanglement negativity, an entanglement measure defined on a bipartite density matrix. We focus on a particular transition previously studied in a toy model of JT gravity, one for which the sum over permutations was found to give similar (or even stronger) enhanced corrections. We derive and resum the relevant permutations to give a form for the averaged negativity spectrum, reproducing the gravitational answer for some quantities and finding tension with other quantities, namely the partially transposed entropy. Along the way, we extend the results of Dong and Wang to the case of $n < 1$ R\'enyi entropy, showing that it always receives volume law corrections.