Wigner negativity in spin-j systems

作     者：Jack Davis Meenu Kumari Robert B. Mann Shohini Ghose 

作者机构：Department of Physics and Astronomy University of Waterloo Waterloo Ontario N2L 3G1 Canada Institute for Quantum Computing University of Waterloo Waterloo Ontario N2L 3G1 Canada Perimeter Institute for Theoretical Physics 31 Caroline Street North Waterloo Ontario N2L 2Y5 Canada Department of Physics and Computer Science Wilfrid Laurier University Waterloo Ontario N2L 3C5 Canada 

出 版 物：《Physical Review Research》 (Phys. Rev. Res.)

年 卷 期：2021年第3卷第3期

页      面：033134-033134页

核心收录：

基　　金：Natural Sciences and Engineering Research Council of Canada (NSERC) Perimeter Institute for Theoretical Physics Government of Canada through the Department of Innovation, Science, and Economic Development Canada Province of Ontario through the Ministry of Colleges and Universities 

主　　题：Quantum correlations in quantum information Quantum information with atoms & light Quantum optics Atomic ensemble Phase space methods 

摘      要：The nonclassicality of simple spin systems as measured by Wigner negativity is studied on a spherical phase space. Several SU(2)-covariant states with common qubit representations are analyzed: spin coherent states, spin cat (Greenberger-Horne-Zeilinger or N00N) states, and Dicke (W) states. We derive a bound on the Wigner negativity of spin cat states that rapidly approaches the true value as spin increases beyond j≳5. We find that spin cat states are not significantly Wigner negative relative to their Dicke state counterparts of equal dimension. We also find, in contrast to several entanglement measures, that the most Wigner-negative Dicke basis element is spin dependent, and not the equatorial state |j,0〉 (or |j,±1/2〉 for half-integer spins). These results underscore the influence that dynamical symmetry has on nonclassicality and suggest a guiding perspective for finding novel quantum computational applications.