- Autor(in)
- Referenz
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10 see chpt. 55 in ref. [8]
11 S. Schmitt-Rink, C. M. Varma, A. E. Ruckenstein, Phys. Rev. Lett. 63 (1989) 445
12 J. M. Kosterlitz, D. J. Thouless, J. Phys. C6, (1973) 1181
13 P. Minnhagen, Rev. Mod. Phys. 59 (1987) 1001
14 R. Gupta et al., Phys. Rev. Lett. 61 (1988) 1996
15 P. J. M. Denteneer, G. An, J. M. J. van Leeuven, Europhys. Lett. 16 (1991) 5
16 M. Drechsler, Diplomarbeit Universität Göttingen (1991), unpublished; in this work it is also shown that the BCS model is unable to describe the crossover between weak and strong coupling since it neglects the existence of collective modes. As a result the order parameter has no gradient term and Tc would scale like Eb in the strong coupling limit describing the - then irrelevant - break up of strongly bound pairs.
17 B. Mühlschlegel, J. Math. Phys. 3 (1962) 522
1 P. Noziéres, S. Schmitt-Rink, J. Low Temp. Phys. 59 (1985) 195
2 M. Randeria, J. M. Duan, L. Y. Shieh, Phys. Rev. Lett. 62 (1989) 981 and
3 T. M. Rice, J. Math. Phys. 8 (1967) 1581
4 U. Everts, Z. Phys. 199 (1967) 211
5 W. B. Strickfaden, Physica 70 (1973) 320
6 see also A. J. Leggett, J. de Phys. 41 (1980) C7
7 Indeed in two dimensions the existence of a bound state in the two particle problem is a necessary condition for a pairing instability as has been shown by K. Miyake, Progr. Theor. Phys. 69 (1983) 1794
8 see for instance A. L. Fetter, J. D. Walecka, ‘Quantum Theory of Many-Particle Systems’, chpt. 53, Mc Graw Hill, New York 1971
9 see L. S. Schulman ‘Techniques and Applications of Path Integration’ chpt. 21, Wiley, New York 1981
Phys. Rev. B41 (1990) 327
- Seitenbereich
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0015 - 0023
- Schlagwort(e)
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<KWD>Fermion Systems
Quantum fluids
Theory of superconductivity
- Zusammenfsg.
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Starting from a model of free Fermions in two dimensions with an arbitrary strong effective interaction, we derive a Ginzburg-Landau theory describing the crossover from BCS-superconductivity to Bose-condensation. We find a smooth crossover from the standard BCS-limit to a Gross-Pitaevski type equation for the order parameter in a Bose superfluid. The mean field transition temperature exhibits a maximum at a coupling strength, where the behaviour crosses over from BCS to Bose like with corresponding values of 2 Δ<sub>0</sub>/T<sub>c</sub> ≈ 5 which are characteristic for high <I>T</I><sub>c</sub> superconductors.
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