4 papers · 1 filter
Criteria and new classes of k-positive maps
Jinchuan Hou, Chi-Kwong Li, Yiu-Tung Poon +2
We study k-positive maps on operators. Proofs are given to different positivity criteria. Special attention is on positive maps arising in the study of quantum information science.…
Linear maps preserving separability of pure states
Jinchuan Hou, Xiaofei Qi
Linear maps preserving pure states of a quantum system of any dimension are characterized. This is then used to establish a structure theorem for linear maps that preserve separabl…
Fidelity of states in infinite dimensional quantum systems
Jinchuan Hou, Xiaofei Qi
In this paper we discuss the fidelity of states in infinite dimensional systems, give an elementary proof of the infinite dimensional version of Uhlmann's theorem, and then, apply…
Detecting entanglement of states by entries of their density matrices
Xiaofei Qi, Jinchuan Hou
For any bipartite systems, a universal entanglement witness of rank-4 for pure states is obtained and a class of finite rank entanglement witnesses is constructed. In addition, a m…