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JOURNALS // Teoreticheskaya i Matematicheskaya Fizika // Archive

TMF, 2020 Volume 202, Number 1, Pages 116–125 (Mi tmf9760)

This article is cited in 19 papers

Skew information revisited: Its variants and a comparison of them

Shunlong Luo, Yuan Sun

Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing, China

Abstract: Skew information was introduced by Wigner and Yanase in the context of quantum measurements. It was later recognized that skew information in addition to its original significance as a measure of the information content of states admits several interpretations of a more physical and information theory nature. This quantity has now found many applications in quantum information. An intriguing and subtle feature of skew information is the involvement of the square root of quantum states (density operators). Comparing skew information with some of its natural modifications reveals mathematical and also physical reasons for using the square root. We further use skew information to quantify the asymmetry of quantum states with respect to group representations.

Keywords: skew information, square root, convexity, quantum coherence, variance.

Received: 31.05.2019
Revised: 31.05.2019

DOI: 10.4213/tmf9760


 English version:
Theoretical and Mathematical Physics, 2020, 202:1, 104–111

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© Steklov Math. Inst. of RAS, 2026