Extension of the Watanabe-Sagawa-Ueda uncertainty relation for measurement errors to infinite-dimensional systems

Fuente: arXiv
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Main Author: Nogami, Ryosuke
Format: Preprint
Published: 2023
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author Nogami, Ryosuke
author_facet Nogami, Ryosuke
contents We extend the Watanabe--Sagawa--Ueda (WSU) uncertainty relations for measurement errors to infinite-dimensional systems. The original WSU formulation provided a definition of measurement errors with a clear physical interpretation based on quantum estimation theory, but was restricted to finite-dimensional systems, excluding important observables such as position and momentum. Using pseudo-inverse forms of positive-semidefinite forms, we develop a framework for classical and quantum estimation theory for models whose parameter space is the set of full-rank states on an infinite-dimensional Hilbert space, and derive classical and quantum Cramér--Rao inequalities. We extend the WSU measurement errors to both bounded and unbounded operators, and derive corresponding error-error uncertainty relations. The resulting uncertainty relation inequalities are stronger than the original WSU bound due to an improved derivation method. Our results provide a theoretical framework for applying estimation-based uncertainty relations to observables with continuous values in infinite-dimensional systems.
format Preprint
id arxiv_https___arxiv_org_abs_2305_09309
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Extension of the Watanabe-Sagawa-Ueda uncertainty relation for measurement errors to infinite-dimensional systems
Nogami, Ryosuke
Quantum Physics
We extend the Watanabe--Sagawa--Ueda (WSU) uncertainty relations for measurement errors to infinite-dimensional systems. The original WSU formulation provided a definition of measurement errors with a clear physical interpretation based on quantum estimation theory, but was restricted to finite-dimensional systems, excluding important observables such as position and momentum. Using pseudo-inverse forms of positive-semidefinite forms, we develop a framework for classical and quantum estimation theory for models whose parameter space is the set of full-rank states on an infinite-dimensional Hilbert space, and derive classical and quantum Cramér--Rao inequalities. We extend the WSU measurement errors to both bounded and unbounded operators, and derive corresponding error-error uncertainty relations. The resulting uncertainty relation inequalities are stronger than the original WSU bound due to an improved derivation method. Our results provide a theoretical framework for applying estimation-based uncertainty relations to observables with continuous values in infinite-dimensional systems.
title Extension of the Watanabe-Sagawa-Ueda uncertainty relation for measurement errors to infinite-dimensional systems
topic Quantum Physics
url https://arxiv.org/abs/2305.09309