ar X iv : 0 80 2 . 32 21 v 2 [ qu an t - ph ] 4 A pr 2 00 8 Entanglement and Density Matrix of a Block of Spins in AKLT Model

ar X iv : 0 80 8 . 36 90 v 1 [ qu an t - ph ] 2 7 A ug 2 00 8 Entanglement dynamics of two - qubit system in different types of noisy channels ∗

X iv :0 80 8. 36 90 v1 [ qu an tph ] 2 7 A ug 2 00 8 Entanglement dynamics of two-qubit system in different types of noisy channels ∗ C. J. Shan, J. B. Liu, W. W. Cheng, T. K. Liu, Y. X. Huang, and H. Li College of Physics and Electronic Science, Hubei Normal University, Huangshi 435002, China (Dated: August 27, 2008) Abstract In this paper, we study entanglement dynamics of a two-qubit extende...

Entanglement and Density Matrix of a Block of Spins in AKLT Model

We study a 1-dimensional AKLT spin chain, consisting of spins S in the bulk and S/2 at both ends. The unique ground state of this AKLT model is described by the Valence-Bond-Solid (VBS) state. We investigate the density matrix of a contiguous block of bulk spins in this ground state. It is shown that the density matrix is a projector onto a subspace of dimension (S + 1) 2 . This subspace is des...

ar X iv : 0 70 4 . 05 20 v 1 [ qu an t - ph ] 4 A pr 2 00 7 A critical theory of quantum entanglement for the Hydrogen molecule ∗

In this paper we investigate some entanglement properties for the Hydrogen molecule considered as a two interacting spin 1 2 (qubit) model. The entanglement related to the H2 molecule is evaluated both using the von Neumann entropy and the Concurrence and it is compared with the corresponding quantities for the two interacting spin system. Many aspects of these functions are examinated employin...

ar X iv : 0 80 5 . 04 23 v 1 [ qu an t - ph ] 4 M ay 2 00 8 Tripartite entanglement dynamics for atom in a two - mode nonlinear cavity

We study Hamiltonian dynamics of a single two-level atom interacting with two modes in a single cavity, which can also include an optical Kerr nonlinearity. Our model is quite general and is solved analytically and studied numerically, and the model reduces to several well known systems by setting certain parameters in the Hamiltonian to zero. We calculate and discuss entanglement between the t...

ar X iv : 0 80 8 . 10 23 v 1 [ qu an t - ph ] 7 A ug 2 00 8 CATEGORICAL QUANTUM MECHANICS