Optimal Discrimination of Gaussian States by Gaussian Measurements

Fuente: arXiv
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Main Authors: Turner, Leah, Lami, Ludovico, Guta, Madalin, Adesso, Gerardo
Format: Preprint
Published: 2026
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author Turner, Leah
Lami, Ludovico
Guta, Madalin
Adesso, Gerardo
author_facet Turner, Leah
Lami, Ludovico
Guta, Madalin
Adesso, Gerardo
contents Are Gaussian measurements enough to distinguish between Gaussian states? Here, we tackle this question by focusing on the max-relative entropy as an operational distinguishability metric. Given two general multimode Gaussian states, we derive a condition, based on their covariance matrices, that completely determines whether or not there exists an optimal Gaussian measurement achieving the max-relative entropy. When the condition is satisfied, we find this optimal measurement explicitly. When the condition is not met, there is a strict gap between the distinguishability achievable by Gaussian measurements and the unconstrained max-relative entropy in which all measurements are allowed. We illustrate our results in the single-mode setting, and show examples of states for which this gap can be made arbitrarily large, revealing novel instances of Gaussian data hiding.
format Preprint
id arxiv_https___arxiv_org_abs_2603_12182
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Optimal Discrimination of Gaussian States by Gaussian Measurements
Turner, Leah
Lami, Ludovico
Guta, Madalin
Adesso, Gerardo
Quantum Physics
Are Gaussian measurements enough to distinguish between Gaussian states? Here, we tackle this question by focusing on the max-relative entropy as an operational distinguishability metric. Given two general multimode Gaussian states, we derive a condition, based on their covariance matrices, that completely determines whether or not there exists an optimal Gaussian measurement achieving the max-relative entropy. When the condition is satisfied, we find this optimal measurement explicitly. When the condition is not met, there is a strict gap between the distinguishability achievable by Gaussian measurements and the unconstrained max-relative entropy in which all measurements are allowed. We illustrate our results in the single-mode setting, and show examples of states for which this gap can be made arbitrarily large, revealing novel instances of Gaussian data hiding.
title Optimal Discrimination of Gaussian States by Gaussian Measurements
topic Quantum Physics
url https://arxiv.org/abs/2603.12182