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Title: Effect of disorder on the superfluid transition in two-dimensional systems

Abstract

In recent experiments on thin {sup 4}He films absorbed to rough surfaces Luhman and Hallock [Phys. Rev. Lett. 93, 086106 (2004)] attempted to observe Kosterlitz-Thouless (KT) features of the superfluid-normal transition of this strongly disordered two-dimensional (2D) bosonic system. It came as a surprise that while peak of dissipation was measured for a wide range of surface roughness there were no indications of the theoretically expected universal jump of the areal superfluid density for the strongly disordered samples. We test the hypothesis that this unusual behavior is a manifestation of finite-size effects by numerical study of the corresponding 2D bosonic model with strong diagonal disorder. We demonstrate that the discontinuous features of the underlying KT transition are severely smoothed out for finite system sizes (or finite frequency measurements). We resolve the universal discontinuity of the areal superfluid density by fitting our data to the KT renormalization group equations for finite systems. In analogy to our simulations, we suggest that in experiments on strongly disordered 2D bosonic systems the very existence of the KT scenario can and should be revealed only from a proper finite-size scaling of the data (for {sup 4}He films finite-size scaling can be effectively controlled by themore » scaling of finite frequency of measurements). We also show relevance of our conclusions for a wider class of systems, such as superconducting granular films, Josephson junction arrays, and ultracold atomic gases, where similar difficulties appear in experiments designed to verify KT transition (especially in disordered cases)« less

Authors:
 [1]
  1. Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003 (United States)
Publication Date:
OSTI Identifier:
20957805
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. B, Condensed Matter and Materials Physics; Journal Volume: 75; Journal Issue: 14; Other Information: DOI: 10.1103/PhysRevB.75.144512; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BOSONS; DENSITY; EQUATIONS; FILMS; FREQUENCY MEASUREMENT; HELIUM 4; JOSEPHSON JUNCTIONS; NUMERICAL ANALYSIS; RENORMALIZATION; ROUGHNESS; SCALING; SUPERFLUIDITY; SURFACES; TWO-DIMENSIONAL CALCULATIONS

Citation Formats

Balabanyan, Karen G. Effect of disorder on the superfluid transition in two-dimensional systems. United States: N. p., 2007. Web. doi:10.1103/PHYSREVB.75.144512.
Balabanyan, Karen G. Effect of disorder on the superfluid transition in two-dimensional systems. United States. doi:10.1103/PHYSREVB.75.144512.
Balabanyan, Karen G. Sun . "Effect of disorder on the superfluid transition in two-dimensional systems". United States. doi:10.1103/PHYSREVB.75.144512.
@article{osti_20957805,
title = {Effect of disorder on the superfluid transition in two-dimensional systems},
author = {Balabanyan, Karen G.},
abstractNote = {In recent experiments on thin {sup 4}He films absorbed to rough surfaces Luhman and Hallock [Phys. Rev. Lett. 93, 086106 (2004)] attempted to observe Kosterlitz-Thouless (KT) features of the superfluid-normal transition of this strongly disordered two-dimensional (2D) bosonic system. It came as a surprise that while peak of dissipation was measured for a wide range of surface roughness there were no indications of the theoretically expected universal jump of the areal superfluid density for the strongly disordered samples. We test the hypothesis that this unusual behavior is a manifestation of finite-size effects by numerical study of the corresponding 2D bosonic model with strong diagonal disorder. We demonstrate that the discontinuous features of the underlying KT transition are severely smoothed out for finite system sizes (or finite frequency measurements). We resolve the universal discontinuity of the areal superfluid density by fitting our data to the KT renormalization group equations for finite systems. In analogy to our simulations, we suggest that in experiments on strongly disordered 2D bosonic systems the very existence of the KT scenario can and should be revealed only from a proper finite-size scaling of the data (for {sup 4}He films finite-size scaling can be effectively controlled by the scaling of finite frequency of measurements). We also show relevance of our conclusions for a wider class of systems, such as superconducting granular films, Josephson junction arrays, and ultracold atomic gases, where similar difficulties appear in experiments designed to verify KT transition (especially in disordered cases)},
doi = {10.1103/PHYSREVB.75.144512},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
number = 14,
volume = 75,
place = {United States},
year = {Sun Apr 01 00:00:00 EDT 2007},
month = {Sun Apr 01 00:00:00 EDT 2007}
}