Metric-adjusted skew information: Convexity and restricted forms of superadditivity

TY - JOUR

T1 - Metric-adjusted skew information

T2 - Convexity and restricted forms of superadditivity

AU - Liang, Cai

AU - Hansen, Frank

PY - 2010

Y1 - 2010

N2 - We give a truly elementary proof of the convexity of metric-adjusted skew information following an idea of Effros. We extend earlier results of weak forms of superadditivity to general metric-adjusted skew information. Recently, Luo and Zhang introduced the notion of semi-quantum states on a bipartite system and proved superadditivity of the Wigner-Yanase-Dyson skew informations for such states. We extend this result to the general metric-adjusted skew information. We finally show that a recently introduced extension to parameter values 1 < p ≤ 2 of the WYD-information is a special case of (unbounded) metric-adjusted skew information.

AB - We give a truly elementary proof of the convexity of metric-adjusted skew information following an idea of Effros. We extend earlier results of weak forms of superadditivity to general metric-adjusted skew information. Recently, Luo and Zhang introduced the notion of semi-quantum states on a bipartite system and proved superadditivity of the Wigner-Yanase-Dyson skew informations for such states. We extend this result to the general metric-adjusted skew information. We finally show that a recently introduced extension to parameter values 1 < p ≤ 2 of the WYD-information is a special case of (unbounded) metric-adjusted skew information.

KW - Faculty of Social Sciences

KW - Wigner–Yanase–Dyson skew information

KW - monotone metric

KW - metric-adjusted skew information

KW - subadditivity

U2 - 10.1007/s11005-010-0396-2

DO - 10.1007/s11005-010-0396-2

M3 - Journal article

SN - 0921-3767

VL - 93

SP - 1

EP - 13

JO - Mathematical Physics Studies

JF - Mathematical Physics Studies

IS - 1

ER -