Regensburg 1998 – wissenschaftliches Programm
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SYD: Symposium Phasenübergänge in Elektronensystemen mit Wechselwirkung
SYD 3: Phasenübergänge in Elektronensystemen mit Wechselwirkung III - Poster
SYD 3.3: Poster
Donnerstag, 26. März 1998, 14:30–17:30, B
Interaction-dependent enhancement of the localization length for two-interacting particles in a one-dimensional random potential — •R. A. Römer2, M. Leadbeater1, and M. Schreiber2 — 1Max-Planck-Institut für Physik komplexer Systeme, D-01187 Dresden — 2Institut für Physik, Technische Universität Chemnitz, D-09107 Chemnitz
In one dimension (1D), bosonization of the repulsive Hubbard model in the gapless phase shows that (onsite) disorder is a relevant perturbation and the ground state corresponds to a strongly localized phase. However, Shepelyansky [1] recently argued that the Hubbard interaction between two particles in a random potential would reduce the localization in comparison with independent particles. We present calculations of the two-particle localization length λ2,M in dependence on disorder (W), interaction strength (U) and system size M. λ2,M is computed by a decimation method from the decay of the Green function along the diagonal of finite samples. The infinite sample estimate λ2,∞ is obtained from finite-size scaling. For U=0 we reproduce the well-known dependence of λ1 on W. For finite U, we find that
| λ2,∞ ∼ λ1α(U) (1) |
with α(U) varying between α(0)=1 and α(1)=1.8.
[1] D. L. Shepelyansky, Phys. Rev. Lett. 73, 2607 (1994)