Collision-model approach to steering of an open driven qubit

: Beyer Konstantin, Luoma Kimmo, Strunz Walter T

Publisher: AMER PHYSICAL SOC

: 2018

: Physical Review A

: PHYSICAL REVIEW A

: PHYS REV A

: ARTN 032113

: 97

: 3

: 10

: 2469-9926

DOI: https://doi.org/10.1103/PhysRevA.97.032113

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 nonadaptive 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.