Floquet-Anderson localization in the Thouless pump and how to avoid it

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Main Authors: Grabarits, András, Takács, Attila, Fulga, Ion Cosma, Asbóth, János K.
Format: Preprint
Published: 2023
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author Grabarits, András
Takács, Attila
Fulga, Ion Cosma
Asbóth, János K.
author_facet Grabarits, András
Takács, Attila
Fulga, Ion Cosma
Asbóth, János K.
contents We investigate numerically how onsite disorder affects conduction in the periodically driven Rice-Mele model, a prototypical realization of the Thouless pump. Although the pump is robust against disorder in the fully adiabatic limit, much less is known about the case of finite period time $T$, which is relevant also in light of recent experimental realizations. We find that at any fixed period time and nonzero disorder, increasing the system size $L\to\infty$ always leads to a breakdown of the pump, indicating Anderson localization of the Floquet states. Our numerics indicate, however, that in a properly defined thermodynamic limit, where $L/T^θ$ is kept constant, Anderson localization can be avoided, and the charge pumped per cycle has a well-defined value -- as long as the disorder is not too strong. The critical exponent $θ$ is not universal, rather, its value depends on the disorder strength. Our findings are relevant for practical, experimental realizations of the Thouless pump, for studies investigating the nature of its current-carrying Floquet eigenstates, as well as the mechanism of the full breakdown of the pump, expected if the disorder exceeds a critical value.
format Preprint
id arxiv_https___arxiv_org_abs_2309_12882
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Floquet-Anderson localization in the Thouless pump and how to avoid it
Grabarits, András
Takács, Attila
Fulga, Ion Cosma
Asbóth, János K.
Disordered Systems and Neural Networks
Mesoscale and Nanoscale Physics
We investigate numerically how onsite disorder affects conduction in the periodically driven Rice-Mele model, a prototypical realization of the Thouless pump. Although the pump is robust against disorder in the fully adiabatic limit, much less is known about the case of finite period time $T$, which is relevant also in light of recent experimental realizations. We find that at any fixed period time and nonzero disorder, increasing the system size $L\to\infty$ always leads to a breakdown of the pump, indicating Anderson localization of the Floquet states. Our numerics indicate, however, that in a properly defined thermodynamic limit, where $L/T^θ$ is kept constant, Anderson localization can be avoided, and the charge pumped per cycle has a well-defined value -- as long as the disorder is not too strong. The critical exponent $θ$ is not universal, rather, its value depends on the disorder strength. Our findings are relevant for practical, experimental realizations of the Thouless pump, for studies investigating the nature of its current-carrying Floquet eigenstates, as well as the mechanism of the full breakdown of the pump, expected if the disorder exceeds a critical value.
title Floquet-Anderson localization in the Thouless pump and how to avoid it
topic Disordered Systems and Neural Networks
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2309.12882