Squashed quantum non-Markovianity: a measure of genuine quantum non-Markovianity in states

Fuente: arXiv
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Main Authors: Gangwar, Rajeev, Pandit, Tanmoy, Goswami, Kaumudibikash, Das, Siddhartha, Bera, Manabendra Nath
Format: Preprint
Published: 2023
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author Gangwar, Rajeev
Pandit, Tanmoy
Goswami, Kaumudibikash
Das, Siddhartha
Bera, Manabendra Nath
author_facet Gangwar, Rajeev
Pandit, Tanmoy
Goswami, Kaumudibikash
Das, Siddhartha
Bera, Manabendra Nath
contents Quantum non-Markovianity in tripartite quantum states $ρ_{ABC}$ represents a correlation between systems $A$ and $C$ when conditioned on the system $B$ and is known to have both classical and quantum contributions. However, a systematic characterization of the latter is missing. To address this, we propose a faithful measure for non-Markovianity of genuine quantum origin called squashed quantum non-Markovianity (sQNM). It is based on the quantum conditional mutual information and is defined by the left-over non-Markovianity after squashing out all non-quantum contributions. It is lower bounded by the squashed entanglement between non-conditioning systems in the reduced state and is delimited by the extendibility of either of the non-conditioning systems. We show that the sQNM is monogamous, asymptotically continuous, convex, additive on tensor-product states, and generally super-additive. We characterize genuine quantum non-Markovianity as a resource via a convex resource theory after identifying free states with vanishing sQNM and free operations that do not increase sQNM in states. We use our resource-theoretic framework to bound the rate of state transformations under free operations and to study state transformation under non-free operations; in particular, we find the quantum communication cost from Bob ($B$) to Alice ($A$) or Charlie ($C$) is lower bounded by the change in sQNM in the states. The sQNM finds operational meaning; in particular, the optimal rate of private communication in a variant of conditional one-time pad protocol is twice the sQNM. Also, the minimum deconstruction cost for a variant of quantum deconstruction protocol is given twice the sQNM of the state.
format Preprint
id arxiv_https___arxiv_org_abs_2311_18323
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Squashed quantum non-Markovianity: a measure of genuine quantum non-Markovianity in states
Gangwar, Rajeev
Pandit, Tanmoy
Goswami, Kaumudibikash
Das, Siddhartha
Bera, Manabendra Nath
Quantum Physics
Other Condensed Matter
High Energy Physics - Theory
Mathematical Physics
Quantum non-Markovianity in tripartite quantum states $ρ_{ABC}$ represents a correlation between systems $A$ and $C$ when conditioned on the system $B$ and is known to have both classical and quantum contributions. However, a systematic characterization of the latter is missing. To address this, we propose a faithful measure for non-Markovianity of genuine quantum origin called squashed quantum non-Markovianity (sQNM). It is based on the quantum conditional mutual information and is defined by the left-over non-Markovianity after squashing out all non-quantum contributions. It is lower bounded by the squashed entanglement between non-conditioning systems in the reduced state and is delimited by the extendibility of either of the non-conditioning systems. We show that the sQNM is monogamous, asymptotically continuous, convex, additive on tensor-product states, and generally super-additive. We characterize genuine quantum non-Markovianity as a resource via a convex resource theory after identifying free states with vanishing sQNM and free operations that do not increase sQNM in states. We use our resource-theoretic framework to bound the rate of state transformations under free operations and to study state transformation under non-free operations; in particular, we find the quantum communication cost from Bob ($B$) to Alice ($A$) or Charlie ($C$) is lower bounded by the change in sQNM in the states. The sQNM finds operational meaning; in particular, the optimal rate of private communication in a variant of conditional one-time pad protocol is twice the sQNM. Also, the minimum deconstruction cost for a variant of quantum deconstruction protocol is given twice the sQNM of the state.
title Squashed quantum non-Markovianity: a measure of genuine quantum non-Markovianity in states
topic Quantum Physics
Other Condensed Matter
High Energy Physics - Theory
Mathematical Physics
url https://arxiv.org/abs/2311.18323