Maximal intrinsic randomness of noisy quantum measurements

Fuente: arXiv
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Main Authors: Curran, Fionnuala, Moradi, Morteza, Senno, Gabriel, Stobinska, Magdalena, Acín, Antonio
Format: Preprint
Published: 2025
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author Curran, Fionnuala
Moradi, Morteza
Senno, Gabriel
Stobinska, Magdalena
Acín, Antonio
author_facet Curran, Fionnuala
Moradi, Morteza
Senno, Gabriel
Stobinska, Magdalena
Acín, Antonio
contents Quantum physics exhibits an intrinsic and private form of randomness with no classical counterpart. Any setup for quantum randomness generation involves measurements acting on quantum states. In this work, we consider the following question: Given a quantum measurement, how much randomness can be generated from it? In real life, measurements are noisy and thus contain an additional, extrinsic form of randomness due to ignorance. This extrinsic randomness is not private since, in an adversarial model, it takes the form of quantum side information held by an eavesdropper who can use it to predict the measurement outcomes. Randomness of measurements is then quantified by the guessing probability of this eavesdropper, when minimized over all possible input states. This optimization is in general hard to compute, but we solve it here for any two-outcome qubit measurement and for projective measurements in arbitrary dimension mixed with white noise. We also construct, for a given measured probability distribution, different realizations with (i) a noisy state and noiseless measurement (ii) a noiseless state and noisy measurement and (iii) a noisy state and measurement, and we show that the latter gives an eavesdropper significantly higher guessing power.
format Preprint
id arxiv_https___arxiv_org_abs_2506_22294
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Maximal intrinsic randomness of noisy quantum measurements
Curran, Fionnuala
Moradi, Morteza
Senno, Gabriel
Stobinska, Magdalena
Acín, Antonio
Quantum Physics
Quantum physics exhibits an intrinsic and private form of randomness with no classical counterpart. Any setup for quantum randomness generation involves measurements acting on quantum states. In this work, we consider the following question: Given a quantum measurement, how much randomness can be generated from it? In real life, measurements are noisy and thus contain an additional, extrinsic form of randomness due to ignorance. This extrinsic randomness is not private since, in an adversarial model, it takes the form of quantum side information held by an eavesdropper who can use it to predict the measurement outcomes. Randomness of measurements is then quantified by the guessing probability of this eavesdropper, when minimized over all possible input states. This optimization is in general hard to compute, but we solve it here for any two-outcome qubit measurement and for projective measurements in arbitrary dimension mixed with white noise. We also construct, for a given measured probability distribution, different realizations with (i) a noisy state and noiseless measurement (ii) a noiseless state and noisy measurement and (iii) a noisy state and measurement, and we show that the latter gives an eavesdropper significantly higher guessing power.
title Maximal intrinsic randomness of noisy quantum measurements
topic Quantum Physics
url https://arxiv.org/abs/2506.22294