Diffusive transport in a quasiperiodic Fibonacci chain: absence of many-body localization at small interactions
| Autor: | Marko Žnidarič, Vipin Kerala Varma |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Physics
Quantum Physics Fibonacci number Strongly Correlated Electrons (cond-mat.str-el) Dynamics (mechanics) FOS: Physical sciences 02 engineering and technology Function (mathematics) Disordered Systems and Neural Networks (cond-mat.dis-nn) Condensed Matter - Disordered Systems and Neural Networks 021001 nanoscience & nanotechnology 01 natural sciences Condensed Matter - Strongly Correlated Electrons Magnetization Chain (algebraic topology) Quasiperiodic function 0103 physical sciences Exponent Statistical physics Diffusion (business) 010306 general physics 0210 nano-technology Quantum Physics (quant-ph) |
| Zdroj: | Physical Review B |
| DOI: | 10.48550/arxiv.1905.03128 |
| Popis: | We study high-temperature magnetization transport in a many-body spin-1/2 chain with on-site quasiperiodic potential governed by the Fibonacci rule. In the absence of interactions it is known that the system is critical with the transport described by a continuously varying dynamical exponent (from ballistic to localized) as a function of the on-site potential strength. Upon introducing weak interactions, we find that an anomalous noninteracting dynamical exponent becomes diffusive for any potential strength. This is borne out by a boundary-driven Lindblad dynamics as well as unitary dynamics, with agreeing diffusion constants. This must be contrasted to random potential where transport is subdiffusive at such small interactions. Mean-field treatment of the dynamics for small U always slows down the non-interacting dynamics to subdiffusion, and is therefore unable to describe diffusion in an interacting quasiperiodic system. Finally, briefly exploring larger interactions we find a regime of interaction-induced subdiffusive dynamics, despite the on-site potential itself having no "rare-regions". Comment: 16 pages; v2: additional more precise data for subdiffusion in Fig.6 |
| Databáze: | OpenAIRE |
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