In a seminal study of quantum states with Einstein–Podolsky–Rosen correlations
(entanglement) admitting a hidden-variable model (Werner, 1989), Werner introduced the …

A nondestructive approach to determine an unknown two-qubit Werner state of an ensemble
is proposed. The approach is feasible for all four types of Werner states which contain …

We present a nondemolition quantum information processing task of probing the information
of a class of quantum state. In this task, the information is extracted by some unitary …

Brown et al. and Borras et al. have explored numerical optimization procedures to search for
highly entangled five-and six-qubit states. Here, we give a relation between the genuine …

Pairwise quantum correlations in the ground state of an N-spins antiferromagnetic
Heisenberg chain are investigated. By varying the exchange coupling between two …

Decoy-state quantum key distribution (QKD) has become the most efficient method to resist
the photon-number-splitting (PNS) attack and estimate the secure key rate. The decoy-state …

We propose a scheme for identifying an unknown Bell diagonal state. In our scheme the
measurements are performed on the probe qubits instead of the Bell diagonal state. The …

The operator entanglement of two-qubit joint unitary operations is revisited. The Schmidt
number, an important attribute of a two-qubit unitary operation, may have connection with …

We propose a scheme for the non-destructive detection of an unknown Werner state by
detecting the steady-state output intensity of the probe field. Moreover, with a similar …

We propose new methods to construct universal Greenberger-Horne-Zeilinger (GHZ)-state
analyzers without destroying the qubits by using two-qubit parity gates. The idea can be …