9 citations · 12 across the 7 of their papers we have counts for
7 papers
Optimal Bounds on Functions of Quantum States under Quantum Channels
Chi-Kwong Li, Diane Christine Pelejo, Kuo-Zhong Wang
Let be quantum states and be a scalar function such as the trace norm, the fidelity, and the relative entropy, etc. We determine optimal…
Product of two positive contractions
Chi-Kwong Li, Diane Christine Pelejo, Kuo-Zhong Wang
Several characterizations are given for a square matrix that can be written as the product of two positive (semidefinite) projections. Based on one of these characterizations, and…
Numerical Ranges of the product of Operators
Hongke Du, Chi-Kwong Li, Kuo-Zhong Wang +2
We study containment regions of the numerical range of the product of operators and such that and are line segments. It is shown that the containment region i…
Minkowski product of convex sets and product numerical range
Chi-Kwong Li, Diane Christine Pelejo, Yiu-Tung Poon +1
Let be two compact convex sets in . Their Minkowski product is the set . We show that the set is star-shaped i…
The spectrum of the product of operators, and the product of their numerical ranges
Chi-Kwong Li, Ming-Cheng Tsai, Kuo-Zhong Wang +1
We show that a compact operator is a multiple of a positive semi-definite operator if and only if $$ σ(AB) \subseteq \overline{W(A)W(B)}, \quad\text{for all (rank one) operator…
Numerical Radii for Tensor Products of Matrices
Hwa-Long Gau, Kuo-Zhong Wang, Pei Yuan Wu
For -by- and -by- complex matrices and , it is known that the inequality holds, where and denote, respectively…