SciPost Phys. 6, 050 (2019) ·
published 29 April 2019

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We study the manybody localization (MBL) properties of a chain of
interacting fermions subject to a quasiperiodic potential such that the
noninteracting chain is always delocalized and displays multifractality.
Contrary to naive expectations, adding interactions in this systems does not
enhance delocalization, and a MBL transition is observed. Due to the local
properties of the quasiperiodic potential, the MBL phase presents specific
features, such as additional peaks in the density distribution. We furthermore
investigate the fate of multifractality in the ergodic phase for low potential
values. Our analysis is based on exact numerical studies of eigenstates and
dynamical properties after a quench.
SciPost Phys. 2, 011 (2017) ·
published 24 March 2017

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Using quantum Monte Carlo simulations, we compute the participation
(ShannonR\'enyi) entropies for groundstate wave functions of Heisenberg
antiferromagnets for onedimensional (line) subsystems of length $L$ embedded
in twodimensional ($L\times L$) square lattices. We also study the line
entropy at finite temperature, i.e. of the diagonal elements of the density
matrix, for threedimensional ($L\times L\times L$) cubic lattices. The
breaking of SU(2) symmetry is clearly captured by a universal logarithmic
scaling term $l_q\ln L$ in the R\'enyi entropies, in good agreement with the
recent fieldtheory results of Misguish, Pasquier and Oshikawa
[arXiv:1607.02465]. We also study the dependence of the log prefactor $l_q$ on
the R\'enyi index $q$ for which a transition is detected at $q_c\simeq 1$.