Regensburg 2002 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 17: Postersitzung II: Mesoskopische Systeme (1-19), Supraleiter: Theorie (20-26), Elektronenstruktur, Phononen, Tunneln, Ordnungsparameter (27-33), Schwere Fermionen, Kondo-Systeme (34-45)

TT 17.19: Poster

Mittwoch, 13. März 2002, 14:30–18:00, A

DMRG calculation of the Josephson effect between ultrasmall superconducting grains — •Dominique Gobert, Ulrich Schollwöck, and Jan von Delft — Sektion Physik und CeNS, Ludwigs-Maximilians-Universität, Theresienstr. 37, 80333 München

We study the Josephson effect between two superconducting grains in the limit that the grains become so small that the mean level spacing is comparable to the bulk superconducting gap. We calculate the condensation energy as a function of the phase of the tunneling matrix element and then extract the Josephson energy. This is done within a canonical framework using the Density Matrix Renormalization Group, which has been recently applied to mesoscopic systems by Dukelsky and Sierra [1].

This allows us to study the remnants of the Josephson effect in a regime where the notion of a superconducting order parameter with a well-defined phase is no longer applicable.

[1] J. Dukelsky and G. Sierra, Phys.Rev.B 61, 12302 (2000)