Eur. Phys. J. Plus (2022) 137: 636
https://doi.org/10.1140/epjp/s13360-022-02875-5

Regular Article

Detecting spin nonclassicality via average skew information

¹ Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, 100084, Beijing, China
² Academy of Mathematics and Systems Science, Chinese Academy of Sciences, 100190, Beijing, China
³ School of Mathematical Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China

^b luosl@amt.ac.cn

Received: 17 February 2022
Accepted: 24 May 2022
Published online: 29 May 2022

Abstract

Spin nonclassicality is the discrete analogue of the continuous variable optical nonclassicality, and may be regarded as a resource related to coherence or quantumness of states with respect to an overcomplete basis consisting of spin coherent states. It plays a significant role in some quantum information processing tasks such as quantum computation and quantum metrology. Detecting and quantifying spin nonclassicality, which are of both theoretical and experimental relevance, have attracted much attention in quantum information theory. In this work, by virtue of the Wigner–Yanase skew information and the resolution of identity induced by spin coherent states, we provide an information-theoretic approach to spin nonclassicality, elucidate its basic properties and illustrate it through some important and widely used spin states. In particular, we derive a convenient criterion for detecting spin nonclassicality and use it to certify spin nonclassicality for some prototypical states.