On the possibility of many-body localization in a doped Mott insulator

Abstract

Many-body localization (MBL) is currently a hot issue of interacting systems, in which quantum mechanics overcomes thermalization of statistical mechanics. Like Anderson localization of non-interacting electrons, disorders are usually crucial in engineering the quantum interference in MBL. For translation invariant systems, however, the breakdown of eigenstate thermalization hypothesis due to a \emph{pure} many-body quantum effect is still unclear. Here we demonstrate a possible MBL phenomenon without disorder, which emerges in a lightly doped Hubbard model with very strong interaction. By means of density matrix renormalization group numerical calculation on a two-leg ladder, we show that whereas a single hole can induce a very heavy Nagaoka polaron, two or more holes will form bound pair/droplets which are all localized excitations with flat bands at low energy densities. Consequently, MBL eigenstates of finite energy density can be constructed as composed of these localized droplets spatially separated. We further identify the underlying mechanism for this MBL as due to a novel `Berry phase' of the doped Mott insulator, and show that by turning off this Berry phase either by increasing the anisotropy of the model or by hand, an eigenstate transition from the MBL to a conventional quasiparticle phase can be realized.

11 pages and 9 figures; revised

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Cited by in corpus (8)

• Slow Dynamics in Translation-Invariant Quantum Lattice Models
• Partial breakdown of quantum thermalization in a Hubbard-like model
• Localization in a $t$-$J$ type ladder with translational symmetry
• Charge-spin mutual entanglement: A case study by exact diagonalization of the one hole doped $t$-$J$ loop
• Many-Body Localization in Translational Invariant Diamond Ladders with Flat Bands
• Mottness, Phase String, and High-$T_c$ Superconductivity
• Anomalous Diffusion, Prethermalization, and Particle Binding in an Interacting Flat Band System
• Effect of phase string on single-hole dynamics in the two-leg Hubbard ladder