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TT: Fachverband Tiefe Temperaturen
TT 91: Superconductivity: (General) Theory 1
TT 91.6: Talk
Thursday, March 19, 2015, 12:45–13:00, H 2053
Asymmetric Bethe-Salpeter equation for pairing and condensation — •Klaus Morawetz1,2,3 and Pavel Lipavsky4 — 1Münster University of Applied Sciences,Stegerwaldstrasse 39, 48565 Steinfurt, Germany — 2International Institute of Physics (IIP)Av. Odilon Gomes de Lima 1722, 59078-400 Natal, Brazil — 3Max-Planck-Institute for the Physics of Complex Systems, 01187 Dresden, Germany — 4Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 12116 Prague 2, Czech Republic
The Martin-Schwinger hierarchy of correlations is reexamined to derive the recently proposed asymmetric Bethe-Salpeter equation avoiding unphysical repeated collisions. Exceeding the parquet approximation an asymmetry appears in the selfconsistent propagators. This form is superior over the symmetric selfconsistent one since it provides the Nambu-Gorkov equations and gap equation for fermions and the Beliaev equations for bosons without the use of anomalous propagators. The T-matrix with multiple scattering corrections allows to describe superconductivity above and below the critical temperature by the same theoretical footing and provides e.g. a critical velocity of pair excitation larger than the critical velocity of pair breaking in agreement with the experiments.
[1] B. Sopik, P. Lipavský, M. Männel, K. Morawetz, P. Matlock,
Phys. Rev. B 84 (2011) 094529.
[2] K. Morawetz, J. Stat. Phys. 143 (2011) 482-500.
[3] P. Lipavský, K. Morawetz, B. Sopik, M. Männel,
Eur. Phys. J. B 87 (2013) 8-1-10.