Quantum non-Markovian “casual bystander” environments

Quantum memory effects can be induced even when the (time-dependent) dynamical degrees of freedom associated to environment are not affected at all by open system during their joint coupled evolution. In this paper, based on a completely positive bipartite representation system-environment dynamics, we found more general interactions that lead class quantum non-Markovian ``casual bystander'' environments. General properties resulting dynamics studied with focus correlations, collisional measurement-based representation, and regression hypothesis. Memory also characterized through an operational approach, which in turn allows one detect apply. Single multipartite qubits support exemplify developed results.