arXiv subjects

Tohru Mashiko

Publications and source records attributed to Tohru Mashiko.

4 recordsLinked to original sources

arXiv2024

Quantum phase transition between spin liquid and spin nematics in spin-1 Kitaev honeycomb model

Besides the exactly solvable spin-1/2 Kitaev model, higher spin-$S$ ones, not exactly solvable, are promising playgrounds for researches on the quantum spin liquid as well. One of the main interests in higher spin-S cases is the interplay between the Kitaev spin liquid (KSL) and spin nematics. We probe this interplay in a spin-1 model on the honeycomb lattice with competing bilinear-biquadratic and Kitaev interactions. Utilizing the 2D infinite projected entangled-pair state (iPEPS), we map out the phase diagram for the ferro-biquadratic interaction. In the phase diagram, we discover the direct KSL--spin-nematics transitions in the vicinity of pure Kitaev limits. It has been revealed that the ferro KSL exhibits robustness against perturbations from ferro-quadrupolar interactions. Also, the spin-nematic phase is extended to the parameter region near the antiferro-Kitaev limit.

cond-mat.stat-mech↗

arXiv2023

Critical phenomena around the SU(3) symmetric tri-critical point of a spin-1 chain

We investigate critical phenomena of a spin-1 chain in the vicinity of the SU(3) symmetric critical point, which we already specified in the previous study. We numerically diagonalize a Hamiltonian combining the bilinear-biquadratic (BLBQ) Hamiltonian with the trimer Hamiltonian. We then discuss the numerical results based on the conformal field theory (CFT) and the renormalization group. As a result, we firstly verify that the critical point found in our previous study is the tri-critical point among the Haldane phase, trimer phase, and the trimer liquid (TL) phase. Secondly, with regard to the TL--trimer transition and TL--Haldane transition, we find that the critical phenomena around this tri-critical point belong to the Berezinskii--Kosterlitz--Thouless (BKT)-like universality class. We thirdly find the boundary between the Haldane phase and the trimer phase, which is illustrated by the massive self-dual sine-Gordon (SDSG) model.

cond-mat.stat-mech↗

arXiv2021

Phase transition of an SU(3) symmetric spin-1 chain

We investigate a phase transition in an SU(3) symmetric spin-1 chain. We identify the universality class of the critical trimer liquid phase, as well as the phase boundary between these two phases.

cond-mat.stat-mech↗

arXiv2021

Universality Class around the SU(3) Symmetric Point of the Dimer-Trimer Spin-1 Chain

We study critical phenomena of the SU(3) symmetric spin-1 chains when adding the SU(3) asymmetric term. To investigate such system, we numerically diagonalize the Dimer-Trimer (DT) model Hamiltonian around the SU(3) symmetric point, named the pure trimer (PT) point. We analyze our numerical results with the conformal field theory (CFT). First of all, we discover soft modes at the wave number q = 0 and q = 2π/3 for the PT point, and then the system is critical. Secondly, we find that the system at the PT point belongs to the CFT with the central charge c = 2 and the scaling dimension x = 2/3. Finally, by investigating the eigenvalues of the Hamiltonian in the vicinity of the PT point, we find that there is a phase transition at the PT point from a massive phase to a massless phase. From these numerical results, the phase transition at the PT point belongs to the Berezinskii-Kosterlitz-Thouless (BKT)-like universality class that is explained by the level-1 SU(3) Wess-Zumino-Witten (SU(3) 1 WZW) model.

cond-mat.stat-mech↗