9 papers
Quasi-periodic flat-band model constructed by molecular-orbital representation
Tomonari Mizoguchi, Yasuhiro Hatsugai
We construct a tight-binding model that hosts both a quasi-periodic nature and marcoscopically-dengenerate zero-energy modes. The model can be regarded as a counterpart of the Aubr…
Topological photonics of generalized and nonlinear eigenvalue equations
Takuma Isobe, Tsuneya Yoshida, Yasuhiro Hatsugai
Topological photonics is developed based on the analogy of Schrödinger equation which is mathematically reduced to a standard eigenvalue equation. Notably, several photonic system…
Topological pump and its plateau transitions of -leg spin ladder
Kota Yamamoto, Yoshihito Kuno, Tomonari Mizoguchi +2
A topological pump on an leg spin ladder is discussed by introducing spatial clusterization whose adiabatic limit is a set of site staircase clusters. We…
Topological-to-Topological Transition Induced by On-Site Nonlinearity in a One-Dimensional Topological Insulator
Kazuki Sone, Yasuhiro Hatsugai
Recent studies have extended the notion of band topology to nonlinear systems by defining nonlinear counterparts of eigenvalue problems. They have found the nonlinearity-induced to…
Topological domain-wall pump with spontaneous symmetry breaking
Yoshihito Kuno, Yasuhiro Hatsugai
A domain-wall pump by an extended cluster model of spins is proposed with local gauge invariance. Its snapshot ground state is gapped and doubly degenerated due to $…
Evolution of flat bands in two-dimensional fused pentagon network
Tomonari Mizoguchi, Mina Maruyama, Yasuhiro Hatsugai +1
Theoretical quest of flat-band tight-binding models usually relies on lattice structures on which electrons reside. Typical examples of candidate lattice structures include the Lie…