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Main Authors: Otto, Fynn, Szymański, Konrad
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2401.06064
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author Otto, Fynn
Szymański, Konrad
author_facet Otto, Fynn
Szymański, Konrad
contents Quantum states of angular momentum and spin generally are not invariant under rotations of the reference frame. Therefore, they can be used as a resource of relative orientation, which is encoded in the asymmetry of the state under consideration. In this paper we introduce the analytical characterization of the rotational information by parameterizing the group characteristic function by polynomial functions. By doing so, we show that the set of states achievable through transformations lacking a reference frame (rotationally covariant ones) admits an analytical characterization and can be studied through the use of semidefinite optimization techniques. We demonstrate the developed methods via examples, and provide a physical scenario in which a reference-independent operation performs a metrologically useful operation: the preparation of a state of light improving interferometer sensitivity, which equivalently can be realized as a postprocessing step.
format Preprint
id arxiv_https___arxiv_org_abs_2401_06064
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Rotational covariance restricts available quantum states
Otto, Fynn
Szymański, Konrad
Quantum Physics
Quantum states of angular momentum and spin generally are not invariant under rotations of the reference frame. Therefore, they can be used as a resource of relative orientation, which is encoded in the asymmetry of the state under consideration. In this paper we introduce the analytical characterization of the rotational information by parameterizing the group characteristic function by polynomial functions. By doing so, we show that the set of states achievable through transformations lacking a reference frame (rotationally covariant ones) admits an analytical characterization and can be studied through the use of semidefinite optimization techniques. We demonstrate the developed methods via examples, and provide a physical scenario in which a reference-independent operation performs a metrologically useful operation: the preparation of a state of light improving interferometer sensitivity, which equivalently can be realized as a postprocessing step.
title Rotational covariance restricts available quantum states
topic Quantum Physics
url https://arxiv.org/abs/2401.06064