Entanglement cost for infinite-dimensional physical systems

Fuente: arXiv
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Auteurs principaux: Yamasaki, Hayata, Kuroiwa, Kohdai, Hayden, Patrick, Lami, Ludovico
Format: Preprint
Publié: 2024
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author Yamasaki, Hayata
Kuroiwa, Kohdai
Hayden, Patrick
Lami, Ludovico
author_facet Yamasaki, Hayata
Kuroiwa, Kohdai
Hayden, Patrick
Lami, Ludovico
contents We prove that the entanglement cost equals the regularized entanglement of formation for any infinite-dimensional quantum state $ρ_{AB}$ with finite quantum entropy on at least one of the subsystems $A$ or $B$. This generalizes a foundational result in quantum information theory that was previously formulated only for operations and states on finite-dimensional systems. The extension to infinite-dimensional systems is nontrivial because the conventional tools for establishing both the direct and converse bounds, i.e., strong typicality, monotonicity, and asymptotic continuity, are no longer directly applicable. To address this problem, we construct a new entanglement dilution protocol for infinite-dimensional states implementable by local operations and a finite amount of one-way classical communication (one-way LOCC), using weak and strong typicality multiple times. We also prove the optimality of this protocol among all protocols, even under infinite-dimensional separable operations, by developing an argument based on alternative forms of monotonicity and asymptotic continuity of the entanglement of formation for infinite-dimensional states. Along the way, we derive a new integral representation for the quantum entropy of infinite-dimensional states, which we believe to be of independent interest. Our results allow us to fully characterize an important operational entanglement measure -- the entanglement cost -- for all infinite-dimensional physical systems.
format Preprint
id arxiv_https___arxiv_org_abs_2401_09554
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Entanglement cost for infinite-dimensional physical systems
Yamasaki, Hayata
Kuroiwa, Kohdai
Hayden, Patrick
Lami, Ludovico
Quantum Physics
Mathematical Physics
We prove that the entanglement cost equals the regularized entanglement of formation for any infinite-dimensional quantum state $ρ_{AB}$ with finite quantum entropy on at least one of the subsystems $A$ or $B$. This generalizes a foundational result in quantum information theory that was previously formulated only for operations and states on finite-dimensional systems. The extension to infinite-dimensional systems is nontrivial because the conventional tools for establishing both the direct and converse bounds, i.e., strong typicality, monotonicity, and asymptotic continuity, are no longer directly applicable. To address this problem, we construct a new entanglement dilution protocol for infinite-dimensional states implementable by local operations and a finite amount of one-way classical communication (one-way LOCC), using weak and strong typicality multiple times. We also prove the optimality of this protocol among all protocols, even under infinite-dimensional separable operations, by developing an argument based on alternative forms of monotonicity and asymptotic continuity of the entanglement of formation for infinite-dimensional states. Along the way, we derive a new integral representation for the quantum entropy of infinite-dimensional states, which we believe to be of independent interest. Our results allow us to fully characterize an important operational entanglement measure -- the entanglement cost -- for all infinite-dimensional physical systems.
title Entanglement cost for infinite-dimensional physical systems
topic Quantum Physics
Mathematical Physics
url https://arxiv.org/abs/2401.09554