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

**Authors:** Wilson S. Martins, Diogo O. Soares-Pinto  
**arXiv:** [2110.03490](https://arxiv.org/abs/2110.03490)  
**Date:** 2021-10-07  
**Summary page:** https://www.summarizepaper.com/en/arxiv-id/2110.03490v1/

## Key points

- The study explores behavior of quantum systems interacting with environments, focusing on scenarios with information loss due to correlations with environmental degrees of freedom.
- Non-Markovianity is investigated using the BLP trace-based measure and the conditional past-future correlator (CPF) as witnesses.
- Research centers on a central qubit coupled to a spin chain with Ising interactions under a magnetic field (central spin model).
- Dynamics of the system experiencing dephasing through Kraus operators are solved.
- Sections in the paper describe model system and environment dynamics, analyze coherence functions and Lee-Yang zeros correlation, and present non-Markovianity witnesses plots based on varying parameters.
- Non-Markovian behavior impacts traditional concepts like quantum Darwinism and Spectrum Broadcast Structure (SBS), suppressing classic plateau in Partial Information Plot (PIP) associated with quantum Darwinism and affecting objective information derived from SBS.
- Encoding accessible information for measurement in the environment is not feasible under any model limit.
- Informational aspect explored through quantum Darwinism and SBS frameworks in understanding objectivity emergence.

## Summary

The study explores the behavior of quantum systems interacting with environments, specifically in scenarios where information loss occurs due to correlations with environmental degrees of freedom. Non-Markovianity is investigated, and two specific witnesses are employed to analyze this phenomenon: the BLP trace-based measure and the conditional past-future correlator (CPF). The research focuses on a central qubit coupled to a spin chain with Ising interactions under a magnetic field, known as a central spin model. The exact dynamics of the system experiencing dephasing dynamics through Kraus operators are solved. The paper's structure includes sections dedicated to describing the model system and environment dynamics using Kraus representation, analyzing coherence functions and Lee-Yang zeros correlation, presenting non-Markovianity witnesses plots based on varying parameters like magnetic field strength, Ising coupling, and temperature. Furthermore, the study delves into how this non-Markovian behavior impacts traditional concepts such as quantum Darwinism and Spectrum Broadcast Structure (SBS). It is observed that this behavior suppresses the classic plateau in Partial Information Plot (PIP) associated with quantum Darwinism and affects objective information derived from SBS. Additionally, it is demonstrated that encoding accessible information for measurement in the environment is not feasible under any model limit. The informational aspect of the problem is explored through quantum Darwinism and SBS frameworks in understanding objectivity emergence. Overall, this research sheds light on how information storage in structured thermal baths can be suppressed while highlighting key insights into non-Markovianity phenomena and its implications on objective information retrieval within quantum systems interacting with their environments.