80 citations · 305 across the 9 of their papers we have counts for
6 papers · 1 filter
Quantized Berry Phases of a Spin-1/2 Frustrated Two-Leg Ladder with Four-Spin Exchange
I. Maruyama, T. Hirano, Y. Hatsugai
A spin-1/2 frustrated two-leg ladder with four-spin exchange interaction is studied by quantized Berry phases. We found that the Berry phase successfully characterizes the Haldane…
Topological Identification of Spin-1/2 Two-Leg Ladder with Four-Spin Ring Exchange
I. Maruyama, T. Hirano, Y. Hatsugai
A spin-1/2 two-leg ladder with four-spin ring exchange is studied by quantized Berry phases, used as local order parameters. Reflecting local objects, non-trivial () Berry phase…
Degeneracy and Consistency Condition of Berry phases: Gap Closing under the Twist
Takaaki Hirano, Hosho Katsura, Yasuhiro Hatsugai
We have discussed a consistency condition of Berry phases defined by a local gauge twist and spatial symmetries of the many body system. It imposes a non trivial gap closing condit…
Topological Classification of Gapped Spin Chains :Quantized Berry Phase as a Local Order Parameter
Takaaki Hirano, Hosho Katsura, Yasuhiro Hatsugai
We characterize several phases of gapped spin systems by local order parameters defined by quantized Berry phases. This characterization is topologically stable against any small p…
Entanglement Entropy of One-dimensional Gapped Spin Chains
Takaaki Hirano, Yasuhiro Hatsugai
We investigate the entanglement entropy (EE) of gapped S=1 and spin chains with dimerization. We find that the effective boundary degrees of freedom as edge states contribu…
Exact Analysis of Entanglement in Gapped Quantum Spin Chains
Hosho Katsura, Takaaki Hirano, Yasuhiro Hatsugai
We investigate the entanglement properties of the valence-bond-solid states with generic integer-spin . Using the Schwinger boson representation of the valence-bond-solid states…