Lossless Postselected Quantum Metrology with Quasi-pure Mixed States

Fuente: arXiv
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Main Author: Yang, Jing
Format: Preprint
Published: 2024
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author Yang, Jing
author_facet Yang, Jing
contents Postselection can compress the metrological information and improve sensitivity in the presence of certain types of technical noise. Postselected quantum metrology with pure states has been significantly advanced recently. However, extending this framework to mixed states leads to formidable challenges, such as the difficulty in searching for lossless postselection measurements or even the loss of metrological information. In this work, we leverage the intuition for the lossless postselection of pure states and generalize the theory to the lossless postselection of a class of mixed states, dubbed quasi-pure states. We illustrate our findings in postselected quantum imaging, unitary estimation problems, and show that the quasi-pure structure can be universally engineered through only classical correlation with an ancilla. Our findings extend the utility of postselection techniques to scenarios with decoherence and also offer new perspectives to foundational questions in quantum information geometry.
format Preprint
id arxiv_https___arxiv_org_abs_2405_00405
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Lossless Postselected Quantum Metrology with Quasi-pure Mixed States
Yang, Jing
Quantum Physics
Optics
Postselection can compress the metrological information and improve sensitivity in the presence of certain types of technical noise. Postselected quantum metrology with pure states has been significantly advanced recently. However, extending this framework to mixed states leads to formidable challenges, such as the difficulty in searching for lossless postselection measurements or even the loss of metrological information. In this work, we leverage the intuition for the lossless postselection of pure states and generalize the theory to the lossless postselection of a class of mixed states, dubbed quasi-pure states. We illustrate our findings in postselected quantum imaging, unitary estimation problems, and show that the quasi-pure structure can be universally engineered through only classical correlation with an ancilla. Our findings extend the utility of postselection techniques to scenarios with decoherence and also offer new perspectives to foundational questions in quantum information geometry.
title Lossless Postselected Quantum Metrology with Quasi-pure Mixed States
topic Quantum Physics
Optics
url https://arxiv.org/abs/2405.00405