Coarse-grained quantum state tomography with optimal POVM construction

Fuente: arXiv
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Autores principales: Jung, Donghun, Cho, Young-Wook, Kim, Yosep, Lee, Junghyun
Formato: Preprint
Publicado: 2024
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author Jung, Donghun
Cho, Young-Wook
Kim, Yosep
Lee, Junghyun
author_facet Jung, Donghun
Cho, Young-Wook
Kim, Yosep
Lee, Junghyun
contents Constructing an integrated large-scale qubit system of realistic size requires addressing the challenge of physical crowding among qubits. This constraint poses an issue of coarse-grained (CG) measurement, wherein information from the multi-qubit system is collectively gathered. In this work, we introduce a novel approach to reconstruct the target density matrix from a comprehensive set of Positive Operator-Valued Measures (POVM) using a Parameterized Quantum Circuit (PQC) under the constraint of CG measurement. We improve the robustness and stability of CG quantum state tomography (QST) by optimizing the POVM set to achieve a generalized symmetric informationally complete (GSIC) POVM through maximization of the von Neumann entropy. This optimized construction of CG-POVMs is scalable to an N-qubit system. We further discuss a more efficient construction of N-qubit CG-QST without exponential increases in two-qubit gates or circuit depth per measurement. Our scheme offers a viable pathway towards a detector-efficient large-scale solid-state embedded qubit platform by reconstructing crucial quantum information from collective measurements.
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id arxiv_https___arxiv_org_abs_2404_06285
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Coarse-grained quantum state tomography with optimal POVM construction
Jung, Donghun
Cho, Young-Wook
Kim, Yosep
Lee, Junghyun
Quantum Physics
Constructing an integrated large-scale qubit system of realistic size requires addressing the challenge of physical crowding among qubits. This constraint poses an issue of coarse-grained (CG) measurement, wherein information from the multi-qubit system is collectively gathered. In this work, we introduce a novel approach to reconstruct the target density matrix from a comprehensive set of Positive Operator-Valued Measures (POVM) using a Parameterized Quantum Circuit (PQC) under the constraint of CG measurement. We improve the robustness and stability of CG quantum state tomography (QST) by optimizing the POVM set to achieve a generalized symmetric informationally complete (GSIC) POVM through maximization of the von Neumann entropy. This optimized construction of CG-POVMs is scalable to an N-qubit system. We further discuss a more efficient construction of N-qubit CG-QST without exponential increases in two-qubit gates or circuit depth per measurement. Our scheme offers a viable pathway towards a detector-efficient large-scale solid-state embedded qubit platform by reconstructing crucial quantum information from collective measurements.
title Coarse-grained quantum state tomography with optimal POVM construction
topic Quantum Physics
url https://arxiv.org/abs/2404.06285