Collision model approach to steering of an open driven qubit

TL;DR

This paper explores quantum steering of an open driven qubit using collision models, analyzing how different measurement scenarios on the environment influence the system's conditional evolution and steering capabilities.

Contribution

It introduces a collision model framework for quantum steering, explicitly compares local, adaptive, and nonlocal measurement scenarios, and examines their effectiveness and robustness against thermal noise.

Findings

Nonlocal measurements maximize steering violation at zero temperature.

Steering is more difficult at higher temperatures due to thermal noise.

Steering can occur without bipartite entanglement between system and subenvironments.

Abstract

We investigate quantum steering of an open quantum system by measurements on its environment in the framework of collision models. As an example we consider a coherently driven qubit dissipatively coupled to a bath. We construct local non-adaptive and adaptive as well as nonlocal measurement scenarios specifying explicitly the measured observable on the environment. Our approach shows transparently how the conditional evolution of the open system depends on the type of the measurement scenario and the measured observables. These can then be optimized for steering. The nonlocal measurement scenario leads to maximal violation of the used steering inequality at zero temperature. Further, we investigate the robustness of the constructed scenarios against thermal noise. We find generally that steering becomes harder at higher temperatures. Surprisingly, the system can be steered even when bipartite entanglement between the system and individual subenvironments vanishes.