Jinke Huang | Searcharxiv

arXiv2024

Multiple boundary states in bilayer and decorated Su-Schrieffer-Heeger-like models

Topological boundary states have attracted widespread fascination due to their series of intriguing properties. In this paper, we investigate the multiple boundary states within the two kinds of extended Su-Schrieffer-Heeger (SSH) models. The coexistence of boundary states that exist both in the bulk and band gaps is realized based on the bilayer SSH-like model, which consists of two conventional square-root SSH models that are directly coupled. We further show the square-root topology within the decorated SSH-like model, which supports multiple boundary states that could be embedded into the bulk continuum by tuning the hopping parameters. In addition, the connection between the decorated SSH-like model and its effectively decomposed counterparts is revealed. Our results broaden insight into the multiple boundary states and open up an exciting avenue for the future exploration of square-root topology.

cond-mat.mes-hall↗

arXiv2023

Deformed relativistic Hartree-Bogoliubov theory in continuum with a point-coupling functional. II. Examples of odd Nd isotopes

The aim of this work is to extend the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc) based on the point-coupling density functionals to odd-$A$ and odd-odd nuclei and examine its applicability by taking odd-$A$ Nd isotopes as examples. In the DRHBc theory, the densities and potentials with axial deformation are expanded in terms of Legendre polynomials, and the relativistic Hartree-Bogoliubov equations are solved in a Dirac Woods-Saxon basis to include the continuum effects. For an odd-$A$ or odd-odd nucleus, the blocking effect of unpaired nucleon(s) is taken into account with the equal filling approximation. To determine its ground state, an automatic blocking procedure is adopted, in which the orbital with the lowest quasiparticle energy is blocked during the iteration. This procedure is justified by comparing with the results from the orbital-fixed blocking calculations, in which the blocked orbital near the Fermi surface is fixed during the iteration. The ground states for both light and heavy nuclei can be provided by the automatic blocking procedure as the orbital-fixed blocking procedure, but with considerably reduced computational cost. The numerical details for even-even nuclei are found to be valid for odd-$A$ and odd-odd nuclei as well. Taking Nd isotopes including both even-even and odd-$A$ ones as examples, the calculated ground-state properties with PC-PK1 are in good agreement with the available experimental data. This work paves the way to construct the DRHBc mass table including all even-even, odd-$A$ and odd-odd nuclei in the nuclear chart.

nucl-th↗