Experimental qudit state estimation via point tomography

Point tomography is an approach to the problem of state estimation, which is arguably the most efficient and simple method for modern high-precision quantum information experiments. In this scenario, the experimenter knows the target state that their device should prepare, except that intrinsic syst...

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Main Authors: D. Martínez, L. Pereira, K. Sawada, P. González, J. Cariñe, M. Muñoz, A. Delgado, E. S. Gómez, S. P. Walborn, G. Lima
Format: Article
Language:English
Published: American Physical Society 2025-08-01
Series:Physical Review Research
Online Access:http://doi.org/10.1103/gpfl-wdgg
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author D. Martínez
L. Pereira
K. Sawada
P. González
J. Cariñe
M. Muñoz
A. Delgado
E. S. Gómez
S. P. Walborn
G. Lima
author_facet D. Martínez
L. Pereira
K. Sawada
P. González
J. Cariñe
M. Muñoz
A. Delgado
E. S. Gómez
S. P. Walborn
G. Lima
author_sort D. Martínez
collection DOAJ
description Point tomography is an approach to the problem of state estimation, which is arguably the most efficient and simple method for modern high-precision quantum information experiments. In this scenario, the experimenter knows the target state that their device should prepare, except that intrinsic systematic errors will create small discrepancies in the state actually produced. By introducing a kind of informationally complete measurement, dubbed Fisher-symmetric measurements, point tomography determines deviations from the expected state with optimal efficiency. Moreover, the number of outcomes of a measurement saturating the Gill-Massar limit for reconstructing d-dimensional quantum states can be greatly reduced from ∼4d−3 to only 2d−1 outcomes. Thus, improving the measurement overhead as the dimension increases. Here we demonstrate the experimental viability of point tomography. Using a modern photonic platform constructed with state-of-the-art multicore optical fiber technology, we generate four-dimensional quantum states and implement seven-outcome Fisher-symmetric measurements. Our experimental results exhibit the main feature of point tomography, namely, a precision close to the Gill-Massar limit with a single few-outcome measurement. Specifically, we achieved a precision of (3.81±0.05)/N, while the Gill-Massar limit for d=4 is 3/N (N being the ensemble size).
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spelling doaj-art-0f693cd34493426bbc3cac5a5f2093b22025-08-20T04:00:26ZengAmerican Physical SocietyPhysical Review Research2643-15642025-08-017303311910.1103/gpfl-wdggExperimental qudit state estimation via point tomographyD. MartínezL. PereiraK. SawadaP. GonzálezJ. CariñeM. MuñozA. DelgadoE. S. GómezS. P. WalbornG. LimaPoint tomography is an approach to the problem of state estimation, which is arguably the most efficient and simple method for modern high-precision quantum information experiments. In this scenario, the experimenter knows the target state that their device should prepare, except that intrinsic systematic errors will create small discrepancies in the state actually produced. By introducing a kind of informationally complete measurement, dubbed Fisher-symmetric measurements, point tomography determines deviations from the expected state with optimal efficiency. Moreover, the number of outcomes of a measurement saturating the Gill-Massar limit for reconstructing d-dimensional quantum states can be greatly reduced from ∼4d−3 to only 2d−1 outcomes. Thus, improving the measurement overhead as the dimension increases. Here we demonstrate the experimental viability of point tomography. Using a modern photonic platform constructed with state-of-the-art multicore optical fiber technology, we generate four-dimensional quantum states and implement seven-outcome Fisher-symmetric measurements. Our experimental results exhibit the main feature of point tomography, namely, a precision close to the Gill-Massar limit with a single few-outcome measurement. Specifically, we achieved a precision of (3.81±0.05)/N, while the Gill-Massar limit for d=4 is 3/N (N being the ensemble size).http://doi.org/10.1103/gpfl-wdgg
spellingShingle D. Martínez
L. Pereira
K. Sawada
P. González
J. Cariñe
M. Muñoz
A. Delgado
E. S. Gómez
S. P. Walborn
G. Lima
Experimental qudit state estimation via point tomography
Physical Review Research
title Experimental qudit state estimation via point tomography
title_full Experimental qudit state estimation via point tomography
title_fullStr Experimental qudit state estimation via point tomography
title_full_unstemmed Experimental qudit state estimation via point tomography
title_short Experimental qudit state estimation via point tomography
title_sort experimental qudit state estimation via point tomography
url http://doi.org/10.1103/gpfl-wdgg
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AT adelgado experimentalquditstateestimationviapointtomography
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