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Numerical diagonalization analysis of the ground-state superfluid-localization transition in two dimensions

Yoshihiro Nishiyama
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Abstract

Ground state of the two-dimensional hard-core-boson system in the presence of the quenched random chemical potential is investigated by means of the exact-diagonalization method for the system sizes up to L=5. The criticality and the DC conductivity at the superfluid-localization transition have been controversial so far. We estimate, with the finite-size scaling analysis, the correlation-length and the dynamical critical exponents as nu=2.3(0.6) and z=2, respectively. The AC conductivity is computed with the Gagliano-Balseiro formula, with which the resolvent (dynamical response function) is expressed in terms of the continued-fraction form consisted of Lanczos tri-diagonal elements. Thereby, we estimate the universal DC conductivity as sigma_c(omega=0)=0.135(0.01) ((2e)^2/h).

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Yoshihiro Nishiyama. 1998-12-20. Numerical diagonalization analysis of the ground-state superfluid-localization transition in two dimensions. https://arxiv.org/abs/cond-mat/9812332

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