Dresden 2014 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 8: Critical Phenomena and Phase Transitions
DY 8.9: Vortrag
Montag, 31. März 2014, 17:30–17:45, ZEU 118
Numerical evidence for strong randomness scaling at a superfluid-insulator transition of one dimensional bosons — •Susanne Pielawa1 and Ehud Altman1,2 — 1Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 76100, Israel — 2Department of Physics, University of California, Berkeley, California 94720, USA
We present numerical evidence from Monte-Carlo simulations that the superfluid-insulator quantum phase transition of interacting bosons subject to strong disorder in one dimension is controlled by the strong-randomness critical point. At this critical point the distribution of superfluid stiffness over disorder realizations develops a power-law tail reflecting a universal distribution of weak links. The Luttinger parameter on the other hand does not take on a universal value at this critical point, in marked contrast to the known Berezinskii-Kosterlitz-Thouless-like superfluid-insulator transition in weakly disordered systems. We develop a finite-size scaling procedure which allows us to directly compare the numerical results from systems of linear size up to 1024 sites with theoretical predictions obtained in [PRL 93, 150402 (2004)], using a strong disorder renormalization group approach. The data shows good agreement with the scaling expected at the strong-randomness critical point.