FI G. 15: (Color online). The retrieval efficiency as a functi on of t he time. The parameters are chosen as N = 20 , n = 4 , K = 0 . The maximum retrieval efficiency is also obtain ed aro und the 0 . 12 γ $_{−}$1 = 120 µs . Acknowledgments VI. CONCLUSION 12 Poisson distribution of the photons. The greatest atomic squeezing and the concurrence can be generated when the parameter θ is manipulated to π/ 2 , which means all the sub-Poisson distribution of the photons converts to the atomic squeezing. We also consider the sudden death for the atomic squeezing and the pairwise entanglement under various decoherence channels. For the three typical decoherence channels, the sudden deaths of the atomic squeezing hap- pens later than the sudden death of the concurrence. According to the above investigation, an optimal time for generating the greatest atomic squeezing and pair- wise entanglement is obtained by studying in details the competition between the adiabatic creation of quantum correlation in the atomic ensemble and the decoherences we describe with decoherence channels. The work is supported by National Natural Science Foundation of China under Grant Nos. 10547101 and 10604002, the National Fundamental Research Program of China under Grant No. 2006CB921200. X. Wang is supported by NSFC with grant No.10874151, 10935010, NFRPC with grant No. 2006CB921205; Program for New Century Excellent Talents in University (NCET), and Science Fundation of Chinese University. We investigate the multipartite correlations characte r- ize d by the atomic squeezing beyond the pairwise e n- tan glement in the dark states, which are proposed f or the quantum information storage based on electroma g- netically induced transparency mechanism. The atomic squeezing and the pairwise entanglement can be created by adiabatically manipulating the Rabi frequency of the the classical light field on the atomic ensemble. The atomic squeezing in dark states converts from the sub- Kjægaard and E. S. Polzik, Proc. Nat. Acade. U. S. A. 106 , 10960 (2009). [1] C. Liu, Z. Dutton, C. H. Behroozi, and L. V. Hau, Nature (London) 409 , 490 (2001). [2] M. D. Lukin, Rev. Mod. Phys. 75 , 457 (2003). [3] M. Fleischhauer and M. D. Lukin, Phys. Rev. A 65 , 022314 (2002). [16] M. Abramowitz and I. A. Stegun, Handbook of Mathe- matical Functions, (Dover, New York, 1965). [17] M. Kitagawa and M. Ueda, Phys. Rev. A 47 , 5138 (1993). [18] D. J. Wineland, J. J. Bollinger, W. M. Itano, and D. J. Heinzen, Phys. Rev. A 50 , 67 (1994). [19] G. Tóth, C. Knapp, O. Gühne, and H. J. Briegel, Phys. Rev. Lett. 99 , 250405 (2007); Phys. Rev. A 79 , 042334 (2009). [20] A. Sørensen, L. M. Duan, J. I. Cirac, and P. Zoller, Na- ture (London) 409 , 63 (2001). [21] X. Wang and B. C. Sanders, Phys. Rev. A 68 , 012101 (2003). [4] M. Fleischhauer, S. F. Yelin, M. D. Lukin, Opt. Commun. 179 , 395 (2000). [5] C. P. Sun, Y. Li, and X. F. Liu, Phys. Rev. Lett. 91 , 147903 (2003). [6] R. H. Dicke, Phys. Rev. 93 , 99 (1954). [7] B. Zhao, Y. A. Chen, X. H. Bao, T. Strassel, C. S. Chuu, X. M. Jin, J. Schmiedmayer, Z. S. Yuan, S. Chen and J. W. Pan, Nature Phys. 5 , 95 (2009). [8] Y. O. Dudin, S. D. Jenkins, R. Zhao, D. N. Matsukevich, A. Kuzmich, and T. A. B. Kennedy, Phys. Rev. Lett. 103 , 020505 (2009). [9] M. D. Lukin, S. F. Yelin, and M. Fleischhauer, Phys. Rev. Lett. 84 , 4232 (2000). [22] W. K. Wootters, Phys. Rev. Lett. 80 , 2245 (1998). [23] X. Wang and K. Mølmer, Eur. Phys. J. D 18 , 385 (2002). [24] C. Santori, D. Fattal, K. C. Fu, P. E. Barclay, and R. G. Beausoleil, New J. Phys. 11 , 123009 (2009). [25] S. S. Jang, Y. W. Cheong, J. Kim, and H. W. Lee, Phys. Rev. A 74 , 062112 (2006). [10] W. H. Zurek, Rev. Mod. Phys. 75 , 715 (2003). [11] C. Mewes and M. Fleischhauer, Phys. Rev. A 72 , 022327 (2005). [26] M. Weitz, B. C. Young and S. Chu, Phys. Rev. Lett. 73 , 2563 (1994). [27] R. G. Unanyan, B. W. Shore, and K. Bergmann, Phys. Rev. A 63 , 043405 (2001). [28] I. R. Solá, V. S. Malinovsky, and D. J. Tannor, Phys. Rev. A 60 , 3081 (1999). [29] C. Simon, M. Afzelius, J. Appel, A. Boyer de la Giro- [12] J. Simon and H. Tanji, J. K. Thompson and V. Vuletić, Phys. Rev. Lett. 98 , 183601 (2007). [13] T. Yu and J. H. Eberly, Science 323 , 598 (2009). [14] X. Wang, A. Miranowicz, Y. X. Liu, C. P. Sun, and F. Nori, Phys. Rev. A 80 , 022106 (2010). [15] J. Appel, P. J. Windpassinger, D. Oblak, U. B. Hoff, N.