Diffusive transport in a quasiperiodic Fibonacci chain: absence of many-body localization at weak interactions

Varma, Vipin Kerala (author), Žnidarič, Marko (author)

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 a random potential where transport is subdiffusive at such small interactions. Mean-field treatment of the dynamics for small U always slows down the noninteracting 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.”

• Language: English
• Keywords: condensed matter physics
• Typology: 1.01 - Original Scientific Article
• Organization: FMF - Faculty of Mathematics and Physics
• Publication status: Published
• Publication version: Author Accepted Manuscript
• Year: 2019
• Number of pages: Str. 085105-1-085105-14
• Numbering: Vol. 100, iss. 8
• PID: 20.500.12556/RUL-113037
• UDC: 538.9
• ISSN on article: 2469-9950
• DOI: 10.1103/PhysRevB.100.085105
• COBISS.SI-ID: 3389284
• Publication date in RUL: 29.11.2019

Record is a part of a journal

• Title: Physical review
• Publisher: American Physical Society
• ISSN: 2469-9950
• COBISS.SI-ID: 2997348

Secondary language

• Language: Slovenian
• Keywords: fizika kondenzirane snovi