Abstract
Finite-size effects have been a major and justifiable source of concern for studies of many-body localization, and several works have been dedicated to the subject. In this paper, however, we discuss yet another crucial problem that has received much less attention, that of the lack of self-averaging and the consequent danger of reducing the number of random realizations as the system size increases. By taking this into account and considering ensembles with a large number of samples for all system sizes analyzed, we find that the generalized dimensions of the eigenstates of the disordered Heisenberg spin-1/2 chain close to the transition point to localization are described remarkably well by an exact analytical expression derived for the non-interacting Fibonacci lattice, thus providing an additional tool for studies of many-body localization.
Highlights
The Anderson localization in noninteracting systems has been studied for more than 60 years and it is mostly understood [1,2,3]
In this Letter, we discuss yet another crucial problem that has received much less attention, that of the lack of self-averaging and the consequent danger of reducing the number of random realizations as the system size increases. By taking this into account and considering ensembles with a large number of samples for all system sizes analyzed, we find that the generalized dimensions of the eigenstates of the disordered Heisenberg spin-1/2 chain close to the transition point to localization are described remarkably well by an exact analytical expression derived for the noninteracting Fibonacci lattice, providing an additional tool for studies of many-body localization
We show that when the disorder strength of the spin model gets larger than the interaction strength and it moves away from the strong chaotic regime, the fluctuations of the moments of the energy eigenstates increase as the system size grows, exhibiting a strong lack of self-averaging
Summary
The Anderson localization in noninteracting systems has been studied for more than 60 years and it is mostly understood [1,2,3]. By taking this into account and considering ensembles with a large number of samples for all system sizes analyzed, we find that the generalized dimensions of the eigenstates of the disordered Heisenberg spin-1/2 chain close to the transition point to localization are described remarkably well by an exact analytical expression derived for the noninteracting Fibonacci lattice, providing an additional tool for studies of many-body localization.
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