Suppressing information storage in a structured thermal bath: Objectivity and non-Markovianity

Abstract

Quantum systems interacting with environments tend to have their information lost from transmission through the correlations generated with the degrees of freedom of the environment. For situations where we have non-Markovian environments, the information contained in the environment may return to the system and such effect can be captured by non-Markovian witnesses. In the present work, we use a central qubit coupled to a spin chain with Ising interactions subject to a magnetic field, i.e., a central spin model, and solve the exact dynamics of a system subject to dephasing dynamics via Kraus operators. For such we use two witnesses to analyze the presence of non-Markovianity: the BLP trace-based measure and the conditional past-future correlator (CPF). Furthermore, we see how such behavior suppresses the classic plateau in Partial Information Plot (PIP) from the paradigm of quantum Darwinism, as well as objective information from Spectrum Broadcast Structure (SBS). In addition to the system point of view, we show the impossibility of encoding accessible information for measurement in the environment for any model limit.

On the relation between quantum Darwinism and approximate quantum Markovianity

“…This result is consistent with the numerical works [22][23][24][25][26][27] where the highest redundancy is reached when the dynamics is fully Markovian, the redundancy tends to zero when the dynamics is non-Markovian. (Particularly, [27] also considers the information flow from the environmentpoint-of-view.) With the explicit bounds obtained in this paper, we can further understand the boundary between these two regimes.…”

“…Previous studies on the connection between Quantum Darwinism and quantum (non-)Markovianity relies on specific models. In these model studies [22][23][24][25][26][27], there are strong evidences showing that the presence of non-Markovianity would suppress Quantum Darwinism. However, there are some models [28][29][30] in which the non-Markovian nature of environment does not prevent the appearance of Quantum Darwinism.…”

Correlations, information backflow, and objectivity in a class of pure dephasing models

“…We show that two different microscopic descriptions of the evo-lution that lead to the same reduced dynamics of the system can exhibit significant differences with regards to classical objectivity within the quantum Darwinism framework. Our work therefore demonstrates that the non-Markovian character of an evolution does not necessarily affect a system's ability to redundantly proliferate information to the environment, thus contributing to the ongoing efforts to unravel their relation [28][29][30][31] or possible lack thereof [32,33], note in particular the recent analysis in [34] complementary to ours.…”