Enhancing Quantum State Discrimination with Indefinite Causal Order

Fuente: arXiv
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Main Authors: Kechrimparis, Spiros, Moran, James, Karsa, Athena, Lee, Changhyoup, Kwon, Hyukjoon
Format: Preprint
Published: 2024
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author Kechrimparis, Spiros
Moran, James
Karsa, Athena
Lee, Changhyoup
Kwon, Hyukjoon
author_facet Kechrimparis, Spiros
Moran, James
Karsa, Athena
Lee, Changhyoup
Kwon, Hyukjoon
contents The standard quantum state discrimination problem can be understood as a communication scenario involving a sender and a receiver following these three steps: (i) the sender encodes information in pre-agreed quantum states, (ii) sends them over a noiseless channel, and (iii) the receiver decodes the information by performing appropriate measurements on the received states. In a practical setting, however, the channel is not only noisy but often also unknown, thus altering the states and making optimal decoding generally not possible. In this work, we study this noisy discrimination scenario using a protocol based on indefinite causal order. To this end, we consider the quantum switch and define its higher-order generalisations, which we call superswitches. We find that, for certain channels and ensembles, the guessing probability can be significantly improved compared to both single- and multi-copy state discrimination.
format Preprint
id arxiv_https___arxiv_org_abs_2406_19373
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Enhancing Quantum State Discrimination with Indefinite Causal Order
Kechrimparis, Spiros
Moran, James
Karsa, Athena
Lee, Changhyoup
Kwon, Hyukjoon
Quantum Physics
The standard quantum state discrimination problem can be understood as a communication scenario involving a sender and a receiver following these three steps: (i) the sender encodes information in pre-agreed quantum states, (ii) sends them over a noiseless channel, and (iii) the receiver decodes the information by performing appropriate measurements on the received states. In a practical setting, however, the channel is not only noisy but often also unknown, thus altering the states and making optimal decoding generally not possible. In this work, we study this noisy discrimination scenario using a protocol based on indefinite causal order. To this end, we consider the quantum switch and define its higher-order generalisations, which we call superswitches. We find that, for certain channels and ensembles, the guessing probability can be significantly improved compared to both single- and multi-copy state discrimination.
title Enhancing Quantum State Discrimination with Indefinite Causal Order
topic Quantum Physics
url https://arxiv.org/abs/2406.19373