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Main Authors: Pleasance, Graeme, Neira, Angel E., Merkli, Marco, Petruccione, Francesco
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2505.05433
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author Pleasance, Graeme
Neira, Angel E.
Merkli, Marco
Petruccione, Francesco
author_facet Pleasance, Graeme
Neira, Angel E.
Merkli, Marco
Petruccione, Francesco
contents Collision models (CMs) describe an open system interacting in sequence with elements of an environment, termed ancillas. They have been established as a useful tool for analyzing non-Markovian open quantum dynamics based on the ability to control the environmental memory through simple feedback mechanisms. In this work, we investigate how ancilla-ancilla entanglement can serve as a mechanism for controlling the non-Markovianity of an open system, focusing on an operational approach to generating correlations within the environment. To this end, we first demonstrate that the open dynamics of CMs with sequentially generated correlations between groups of ancillas can be mapped onto a composite CM, where the memory part of the environment is incorporated into an enlarged Markovian system. We then apply this framework to an all-qubit CM, and show that non-Markovian behavior emerges only when the next incoming pair of ancillas are entangled prior to colliding with the system. On the other hand, when system-ancilla collisions precede ancilla-ancilla entanglement, we find the open dynamics to always be Markovian. Our findings highlight how certain qualitative features of inter-ancilla correlations can strongly influence the onset of system non-Markovianity.
format Preprint
id arxiv_https___arxiv_org_abs_2505_05433
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Non-Markovianity in collision models with initial intra-environment correlations
Pleasance, Graeme
Neira, Angel E.
Merkli, Marco
Petruccione, Francesco
Quantum Physics
Collision models (CMs) describe an open system interacting in sequence with elements of an environment, termed ancillas. They have been established as a useful tool for analyzing non-Markovian open quantum dynamics based on the ability to control the environmental memory through simple feedback mechanisms. In this work, we investigate how ancilla-ancilla entanglement can serve as a mechanism for controlling the non-Markovianity of an open system, focusing on an operational approach to generating correlations within the environment. To this end, we first demonstrate that the open dynamics of CMs with sequentially generated correlations between groups of ancillas can be mapped onto a composite CM, where the memory part of the environment is incorporated into an enlarged Markovian system. We then apply this framework to an all-qubit CM, and show that non-Markovian behavior emerges only when the next incoming pair of ancillas are entangled prior to colliding with the system. On the other hand, when system-ancilla collisions precede ancilla-ancilla entanglement, we find the open dynamics to always be Markovian. Our findings highlight how certain qualitative features of inter-ancilla correlations can strongly influence the onset of system non-Markovianity.
title Non-Markovianity in collision models with initial intra-environment correlations
topic Quantum Physics
url https://arxiv.org/abs/2505.05433