[1] Bennett C H and Sicincenzo D P 2000 Nature 404 247

[2]Bennett C H et al 1993 Phys. Rev. Lett. 70 1895

[3]Bennett C H and Wiesener S J 1992 Phys. Rev. Lett.
69 2881

[4]Ekert A K 1991 Phys. Rev. Lett. 67 661

[5]Amesen M C, Bose S and Vedral V 2001 Phys. Rev. Lett.
87 017901

[6]Wang X G 2001 Phys. Rev. A 64 012313

[7]Wang X G 2001 Phys. Lett. A 281 101

[8]Sun Y, Chen Y G and Chen H 2003 Phys. Rev. A 68 044301

[9]Zhou L, Song H S, Guo Y Q and Li C 2003 Phys. Rev. A
68 024301

[10] Wang X G, Fu H C and Solomon A I 2001 J. Phys. A
34 11307

[11] Lidar D A, Bacon D and Whaley K B 1999 Phys. Rev.
Lett. 82 4556

[12]Zheng S B and Guo G C 2000 Phys. Rev. Lett. 85 2392

[13] Loss D and DiViencemzo D P 1998 Phys. Rev. A 57 120

[14] Burkard G, Loss D and DiViencemzo D P 1999 Phys. Rev. B
59 2070

[15] Kane B E 1998 Nature 393 133

[16 Vrijen R et al quant-ph/9905096

[17] Sorensen A and Molmer K 1999 Phys. Rev. Lett.
83 2274

[18] Endrejat J and B\"{uttner H 2005 Phys. Rev. A
71 012305

[19]Wootters W K 1998 Phys. Rev. Lett. 80 2245