No-signalling constrains quantum computation with indefinite causal structure

Fuente: arXiv
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Main Authors: Apadula, Luca, Bisio, Alessandro, Perinotti, Paolo
Format: Preprint
Published: 2022
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author Apadula, Luca
Bisio, Alessandro
Perinotti, Paolo
author_facet Apadula, Luca
Bisio, Alessandro
Perinotti, Paolo
contents Quantum processes with indefinite causal structure emerge when we wonder which are the most general evolutions, allowed by quantum theory, of a set of local systems which are not assumed to be in any particular causal order. These processes can be described within the framework of higher-order quantum theory which, starting from considering maps from quantum transformations to quantum transformations, recursively constructs a hierarchy of quantum maps of increasingly higher order. In this work, we develop a formalism for quantum computation with indefinite causal structures; namely, we characterize the computational structure of higher order quantum maps. Taking an axiomatic approach, the rules of this computation are identified as the most general compositions of higher order maps which are compatible with the mathematical structure of quantum theory. We provide a mathematical characterization of the admissible composition for arbitrary higher order quantum maps. We prove that these rules, which have a computational and information-theoretic nature, are determined by the more physical notion of the signalling relations between the quantum systems of the higher order quantum maps.
format Preprint
id arxiv_https___arxiv_org_abs_2202_10214
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle No-signalling constrains quantum computation with indefinite causal structure
Apadula, Luca
Bisio, Alessandro
Perinotti, Paolo
Quantum Physics
Quantum processes with indefinite causal structure emerge when we wonder which are the most general evolutions, allowed by quantum theory, of a set of local systems which are not assumed to be in any particular causal order. These processes can be described within the framework of higher-order quantum theory which, starting from considering maps from quantum transformations to quantum transformations, recursively constructs a hierarchy of quantum maps of increasingly higher order. In this work, we develop a formalism for quantum computation with indefinite causal structures; namely, we characterize the computational structure of higher order quantum maps. Taking an axiomatic approach, the rules of this computation are identified as the most general compositions of higher order maps which are compatible with the mathematical structure of quantum theory. We provide a mathematical characterization of the admissible composition for arbitrary higher order quantum maps. We prove that these rules, which have a computational and information-theoretic nature, are determined by the more physical notion of the signalling relations between the quantum systems of the higher order quantum maps.
title No-signalling constrains quantum computation with indefinite causal structure
topic Quantum Physics
url https://arxiv.org/abs/2202.10214