Some Entanglement Survives Most Measurements

Fuente: arXiv
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Autores principales: Gonzales, Alvin, Dilley, Daniel, Byrd, Mark
Formato: Preprint
Publicado: 2023
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author Gonzales, Alvin
Dilley, Daniel
Byrd, Mark
author_facet Gonzales, Alvin
Dilley, Daniel
Byrd, Mark
contents To prepare quantum states and extract information, it is often assumed that one can perform a perfectly projective measurement. Such measurements can achieve an uncorrelated system and environment state. However, perfectly projective measurements can be difficult or impossible to perform in practice. We investigate the limitations of repeated non-projective measurements in preparing a quantum system. For an $n$-qubit system initially entangled with its environment and subsequently prepared with measurements, using a sequence of weak measurements, we show that some entanglement remains unless one of the measurement operators becomes perfectly projective through an extreme limiting process. Removing initial (unentangled) correlations between a system and its environment and the scenario where measurement outcomes are not tracked are also discussed. We present results for $n$-qubit and $n$-dimensional input states.
format Preprint
id arxiv_https___arxiv_org_abs_2302_06880
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Some Entanglement Survives Most Measurements
Gonzales, Alvin
Dilley, Daniel
Byrd, Mark
Quantum Physics
To prepare quantum states and extract information, it is often assumed that one can perform a perfectly projective measurement. Such measurements can achieve an uncorrelated system and environment state. However, perfectly projective measurements can be difficult or impossible to perform in practice. We investigate the limitations of repeated non-projective measurements in preparing a quantum system. For an $n$-qubit system initially entangled with its environment and subsequently prepared with measurements, using a sequence of weak measurements, we show that some entanglement remains unless one of the measurement operators becomes perfectly projective through an extreme limiting process. Removing initial (unentangled) correlations between a system and its environment and the scenario where measurement outcomes are not tracked are also discussed. We present results for $n$-qubit and $n$-dimensional input states.
title Some Entanglement Survives Most Measurements
topic Quantum Physics
url https://arxiv.org/abs/2302.06880