Particle fluctuations and the failure of simple effective models for many-body localized phases

Kiefer-Emmanouilidis, Maximilian; Unanyan, Razmik; Fleischhauer, Michael; Sirker, Jesko

doi:10.21468/SciPostPhys.12.1.034

SciPost Physics

Particle fluctuations and the failure of simple effective models for many-body localized phases

Maximilian Kiefer-Emmanouilidis, Razmik Unanyan, Michael Fleischhauer, Jesko Sirker

SciPost Phys. 12, 034 (2022) · published 21 January 2022

doi: 10.21468/SciPostPhys.12.1.034
pdf
Submissions/Reports

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.

TY  - JOUR
PB  - SciPost Foundation
DO  - 10.21468/SciPostPhys.12.1.034
TI  - Particle fluctuations and the failure of simple effective models for many-body localized phases
PY  - 2022/01/21
UR  - https://scipost.org/SciPostPhys.12.1.034
JF  - SciPost Physics
JA  - SciPost Phys.
VL  - 12
IS  - 1
SP  - 034
A1  - Kiefer-Emmanouilidis, Maximilian
AU  - Unanyan, Razmik
AU  - Fleischhauer, Michael
AU  - Sirker, Jesko
AB  - 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.
ER  -

@Article{10.21468/SciPostPhys.12.1.034,
	title={{Particle fluctuations and the failure of simple effective models for many-body localized phases}},
	author={Maximilian Kiefer-Emmanouilidis and Razmik Unanyan and Michael Fleischhauer and Jesko Sirker},
	journal={SciPost Phys.},
	volume={12},
	pages={034},
	year={2022},
	publisher={SciPost},
	doi={10.21468/SciPostPhys.12.1.034},
	url={https://scipost.org/10.21468/SciPostPhys.12.1.034},
}

Cited by 7

Authors / Affiliations: mappings to Contributors and Organizations

See all Organizations.

Funders for the research work leading to this publication