[1] Stamper-Kurn D M, Andrews M R, Chikkatur A P, Inuye S, Miesner
H J, Stenger J and Ketterle W 1998 Phys. Rev. Lett. 80 2027

[2] Chang M-S, Hamley C D, Barrett M D, Sauer J A, Fortier K M,
Zhang W, You L and Chapman M S 2004 Phys. Rev. A 92 140403-1

[3] Ho T L 1998 Phys. Rev. Lett. 81 742

[4] Ho T L and Yip S K 2000 Phys. Rev. Lett. 84 4031

[5] Gu Q and Qiu H B 2007 Phys. Rev. Lett. 98 200401

[6] Tomoya I, Kazushige M and Tetsuo O 1999 Phys. Rev. A
60 4857

[7] Ohmi T and Machida K 1998 J. Phys. Soc. Jpn. 67
1822

[8] Zhang W P, Pu H, Chris S and Pierre M 2002 Phys. Rev.
Lett. 88 060401-1

[9] Li Z D, He P B, Li L, Liang J Q and Liu W M 2005 Phys.
Rev. A 71 053611

[10]Kita T, Mizushima T and Machida K 2005 Phys. Rev. A
66 061601(R)

[11] Greiner M, Bloch I, Mandel O, H"ansch T W and Esslinger T
2001 Phys. Rev. Lett. 87 160405

[12] Moritz H, St"oferle T, K"ohl M and Esslinger T 2003
Phys. Rev. Lett. 91 250402

[13] Paredes B, Widera A, Murgl V, Mandel O, F"olling S, Cirac
I, Shlyapnikov G V, H"onsh T W and Bloch I 2004 Nature 429 277

[14] Bao C G and Li Z B 2004 Phys. Rev. A 70 043620

[15] Bao C G and Li Z B 2005 Phys. Rev. A 72 043614

[16] Bao C G 2006 Front. Phys. Chin. 11 92

[17] Pang W, Li Z B and Bao C G 2007 J. Phys. B 40 577

[18] Salasnich L, Parola A and Reatto L 2002 Phys. Rev. A
65 043614

[19] Dalfovo F and Stringari S 1996 Phys.Rev. A. 53
2477

[20] Jackson A D, Kavoulakis G M and Pethick C J 1998
Phys. Rev. A 58 2417