Witnessing non-Markovianity with Gaussian quantum steering in a collision model

The nonincreasing feature of temporal quantum steering under a completely positive trace-preserving (CPTP) map, as proposed by Chen et al. [Phys. Rev. Lett. 116, 020503 (2016), 10.1103/PhysRevLett.116.020503], has been considered as a practical measure of non-Markovianity. In this paper we utilize an all-optical scheme to simulate a non-Markovian collision model and to examine how Gaussian steering can be used as a tool for quantifying the non-Markovianity of a structured continuous-variable (CV) Gaussian channel. By modifying the reflectivity of the beam splitters (BSs), we are able to tune the degree of non-Markovianity of the channel. After analyzing the non-Markovian degree of the dissipative channel within two steering scenarios, we discovered that the Gaussian-steering-based non-Markovian measure depends the specific scenario because of the asymmetry of Gaussian steering. We also compared the Gaussian-steering-based non-Markovianity to the one based on violation of divisibility of a CPTP map.