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Particle fluctuations and the failure of simple effective models for many-body localized phases
by Maximilian Kiefer-Emmanouilidis, Razmik Unanyan, Michael Fleischhauer, Jesko Sirker
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Submission summary
| Authors (as registered SciPost users): | Maximilian Kiefer-Emmanouilidis |
| Submission information | |
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| Preprint Link: | scipost_202111_00010v2 (pdf) |
| Date accepted: | 2021-12-08 |
| Date submitted: | 2021-12-07 00:49 |
| Submitted by: | Kiefer-Emmanouilidis, Maximilian |
| Submitted to: | SciPost Physics |
| Ontological classification | |
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| Academic field: | Physics |
| Specialties: |
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| Approaches: | Theoretical, Computational |
Abstract
We investigate and compare the particle number fluctuations in the putative many-body localized (MBL) phase of a spinless fermion model with potential disorder and nearest-neighbor interactions with those in the non-interacting case (Anderson localization) and in effective models where only interaction terms diagonal in the Anderson basis are kept. We demonstrate that these types of simple effective models cannot account for the particle number fluctuations observed in the MBL phase of the microscopic model. This implies that assisted and pair hopping terms---generated when transforming the microscopic Hamiltonian into the Anderson basis---cannot be neglected even at strong disorder and weak interactions. As a consequence, it appears questionable if the microscopic model possesses an exponential number of exactly conserved {\it local} charges. If such a set of conserved local charges does not exist, then particles are expected to ultimately delocalize for any finite disorder strength.
Author comments upon resubmission
List of changes
On page 2 we have removed Eq. (2) and have reformulated this part as suggested.
Published as SciPost Phys. 12, 034 (2022)