# Information backflow as a resource for entanglement

## TL;DR

This paper demonstrates that information backflow in non-Markovian quantum systems universally serves as a resource for generating entanglement, regardless of the environment's structure, through quantum optimal control.

## Contribution

It extends the understanding of non-Markovianity as a resource by showing its universal role in entanglement generation across different environmental models.

## Key findings

- Information backflow determines maximum entanglement achievable.
- Universality of the entanglement-NM relation confirmed.
- Quantum optimal control optimizes entanglement based on NM degree.

## Abstract

The issue of whether non-Markovianity (NM) could be considered as a resource in quantum information has been a subject of intense debate for the last years. Recently, a simple mechanism was proposed in which one of the main features of NM, the backflow of information from the environment to the system, represents a fundamental and quantifiable resource for generating entanglement within an open quantum system coupled to a finite and small environment [N. Mirkin, P. Poggi and D. Wisniacki, Phys. Rev. A, 99(2), 020301(R)]. In this work, we extend the universality of this resource mechanism by studying a completely different and more general scheme where the system is coupled to an infinite structured reservoir. Under both setups, we show that the degree of NM univocally determines the optimal degree of entanglement reachable by controlling the open system. This result reveals the universality of a quantitative relation between entanglement and NM by using quantum optimal control.