摘要We study thermal entanglement in a two-superconducting-qubit system in two cases, either identical or distinct. By calculating the concurrence of system, we find that the entangled degree of the system is greatly enhanced in the case of very low temperature and Josephson energies for the identical superconducting qubits and our result is in a good agreement with the experimental data.
Abstract：We study thermal entanglement in a two-superconducting-qubit system in two cases, either identical or distinct. By calculating the concurrence of system, we find that the entangled degree of the system is greatly enhanced in the case of very low temperature and Josephson energies for the identical superconducting qubits and our result is in a good agreement with the experimental data.
[1] Nielsen M and Chuang I 2000 Quantum Computation and Quantum Information (Cambridge: Cambridge University)
[2] Pashkin Y A, Yamamoto T, Astafiev O, Nakamura Y, Averin D V and Tsai J S 2003 Nature 421 823
[3] A J Berkley, Berkley A J, Xu H, Ramos R C, Gubrud M A, Strauch F W, Johnson P R anderson J R, Dragt A J, Lobb C J and Wellstood F C 2003 Science 300 1548
[4] Yu C S and Song H S 2006 Phys. Rev. A 73 022325
[5] Chen K, Albeverio S and Fei S M 2005 Phys. Rev. Lett. 95 210501
[6] Cao M and Zhu S 2005 Phys. Rev. A 71 034311
[7] Souza A M, Reis M S, Soares-Pinto D O, Oliveira I S and Sarthour R S 2008 Phys. Rev. B 77 104402
[8] Contreras-Pulido L D and Aguado R 2008 Phys. Rev. B 77 155420
[9] Yamamoto T, Pashkin Y A, Astafiev O, Nakamura Y and Tsai J S 2003 Nature 425 941
[10] Majer J B, Paauw F G, terHaar A C J, Harmans C J P M and Mooij J E 2005 Phys. Rev. Lett. 94 090501
[11] Vion D, Aassime A, Cottet A, Joyez P, Pothier H, Urbina C, Esteve D and Devoret M H 2002 Science 296 886
[12] Martinis J M, Nam S, Aumentado J and Urbina C 2002 Phys. Rev. Lett. 89 117901
[13] McDermott R, Simmonds R W, Steffen M, Cooper K B, Cicak K, Osborn K D, Oh S, Pappas D P and Martinis J M 2005 Science 307 1299
[14] You J Q and Nori F 2005 Phys. Today 58 42
[15] Lambropoulos P and Petrosyan D 2006 Fundamentals of Quantum Optics and Quantum Information (Berlin: Springer)
[16] Mooij H 2005 Science 307 1210
[17] Izmalkov A, Grajcar M, Ilichev E, Wagner T, Meyer H -G, Smirnov A Y, Amin M H S, Maassen van den Brink A and Zagoskin A M 2004 Phys. Rev. Lett. 93 037003
[18] Kim M D and Cho S Y 2007 Phys. Rev. B 75 134514
[19] Wallraff A, Schuster D I, Blais A, Frunzio L, Huang R- S, Majer J, Kumar S, Girvin S M and Schoelkopf R J 2004 Nature 431 162
[20] Pashkin Y A, Yamamoto T, Astafiev O, Nakamura Y, Averin D V and Tsai J S 2003 Nature 421 823
[21] Tian L J and Qin L G 2010 Eur. Phys. J. D 57 123
[22] Shaw M D, Schneiderman J F, Bueno J, Palmer B S, Delsing P and Echternach P M 2009 Phys. Rev. B 79 014516
[23] Paladino E, Mastellone A, DArrigo A and Falci G 2010 Phys. Rev. B 81 052502
[24] Paraoanu G S 2006 Phys. Rev. B 74 140504(R)
[25] Li J, Chalapat K and Paraoanu G S 2008 Phys. Rev. B 78 064503
[26] Echternach P M, LeDuc H G, Skalare A and McGrath W G, 1999 Proceedings of the Tenth International Symposium on Space Terahertz Technology (Charlottesville: University of Virginia) p 261
[27] Hill S and Wootters W K 1997 Phys. Rev. Lett. 78 5022
[28] Wootters W K 1998 Phys. Rev. Lett. 80 2245
[29] Gunlycke D, Kendon V M, Vedral V and Bose S 2001 Phys. Rev. A 64 042302
2011, Vol. 28 
