Total, quantum, and classical measures of anticoherence for mixed spin states

Fuente: arXiv
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Main Authors: Denis, Jérôme, Lacaille, Tara, Martin, John, Serrano-Ensástiga, Eduardo
Format: Preprint
Published: 2026
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author Denis, Jérôme
Lacaille, Tara
Martin, John
Serrano-Ensástiga, Eduardo
author_facet Denis, Jérôme
Lacaille, Tara
Martin, John
Serrano-Ensástiga, Eduardo
contents Anticoherent spin states have isotropic low-order spin moments and are relevant to direction-independent metrology and quantum reference-frame alignment. In contrast to pure states, for mixed states such isotropy may originate either from genuine quantum correlations or from classical statistical mixing. We introduce an axiomatic framework for mixed-state $t$-anticoherence based on the symmetric qubit embedding. We distinguish total $t$-anticoherence, non-decreasing under SU(2)-covariant channels, from quantum $t$-anticoherence, defined as a resource monotone relative to a chosen total measure and constrained to coincide with it on pure states. This yields a classical contribution as their difference. We construct total measures based on reduced-state purity, Hilbert-Schmidt distance, and cumulative multipoles, and we discuss fidelity-based total candidates. We construct quantum counterparts via convex-roof extensions of pure-state functionals tied to bipartite entanglement in the symmetric sector. We provide explicit mixed-state examples, identify states with maximal quantum anticoherence supported on anticoherent subspaces, study robustness under particle loss for different types of states, and characterize the trade-off between purity and the maximal achievable anticoherence order.
format Preprint
id arxiv_https___arxiv_org_abs_2605_29436
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Total, quantum, and classical measures of anticoherence for mixed spin states
Denis, Jérôme
Lacaille, Tara
Martin, John
Serrano-Ensástiga, Eduardo
Quantum Physics
Anticoherent spin states have isotropic low-order spin moments and are relevant to direction-independent metrology and quantum reference-frame alignment. In contrast to pure states, for mixed states such isotropy may originate either from genuine quantum correlations or from classical statistical mixing. We introduce an axiomatic framework for mixed-state $t$-anticoherence based on the symmetric qubit embedding. We distinguish total $t$-anticoherence, non-decreasing under SU(2)-covariant channels, from quantum $t$-anticoherence, defined as a resource monotone relative to a chosen total measure and constrained to coincide with it on pure states. This yields a classical contribution as their difference. We construct total measures based on reduced-state purity, Hilbert-Schmidt distance, and cumulative multipoles, and we discuss fidelity-based total candidates. We construct quantum counterparts via convex-roof extensions of pure-state functionals tied to bipartite entanglement in the symmetric sector. We provide explicit mixed-state examples, identify states with maximal quantum anticoherence supported on anticoherent subspaces, study robustness under particle loss for different types of states, and characterize the trade-off between purity and the maximal achievable anticoherence order.
title Total, quantum, and classical measures of anticoherence for mixed spin states
topic Quantum Physics
url https://arxiv.org/abs/2605.29436