# Non-Markovian open dynamics from collision models

## TL;DR

This paper explores how convex combinations of collision model-derived dynamical maps remain completely positive but can lose Markovian properties, revealing nuanced behaviors in open quantum system dynamics.

## Contribution

It demonstrates that convex combinations of CP and CP-divisible maps from collision models can be non-Markovian, providing new insights into quantum dynamical map properties.

## Key findings

- Convex combinations preserve complete positivity.
- Such combinations can be non-Markovian.
- Examples with qubit maps illustrate these properties.

## Abstract

Convex combinations of the completely positive (CP) as well as CP-divisible, continuous time dynamical maps arising from collision models are investigated. While the individual maps are both CP and Markovian we find that convex combinations remain CP but not necessarily Markovian. Examples of such combinations for qubit dynamical maps arising from collisional models are worked out and the invertibility, CP-divisibility, P-divisibility as well as Markovian properties of such maps are explored.