no code implementations • 23 Oct 2020 • Takuhiro Ogino, Ryui Kaneko, Satoshi Morita, Shunsuke Furukawa, Naoki Kawashima
We investigate a quantum phase transition between a Neel phase and a valence bond solid (VBS) phase, in each of which a different Z2 symmetry is broken, in a spin-1/2 two-leg XXZ ladder with a four-spin interaction.
Strongly Correlated Electrons
no code implementations • 21 Aug 2019 • Hyun-Yong Lee, Ryui Kaneko, Li Ern Chern, Tsuyoshi Okubo, Youhei Yamaji, Naoki Kawashima, Yong Baek Kim
Recent discovery of the half quantized thermal Hall conductivity in $\alpha$-RuCl$_3$, a candidate material for the Kitaev spin liquid, suggests the presence of a highly entangled quantum state in external magnetic fields.
Strongly Correlated Electrons
no code implementations • 4 Jul 2019 • Hyun-Yong Lee, Ryui Kaneko, Tsuyoshi Okubo, Naoki Kawashima
In particular, the variational energy of the LG state becomes exact(within machine precision) at two limits in the model, and the criticality at one of those is analytically derived from the LG feature.
Strongly Correlated Electrons Statistical Mechanics
no code implementations • 17 Jan 2019 • Hyun-Yong Lee, Ryui Kaneko, Tsuyoshi Okubo, Naoki Kawashima
We provide a framework for understanding the gapless Kitaev spin liquid (KSL) in the language of tensor network(TN).
Strongly Correlated Electrons Quantum Gases Statistical Mechanics
1 code implementation • 23 Feb 2018 • Ryui Kaneko, Yoshihiko Nonomura, Masanori Kohno
We explore the possibility of a Berezinskii-Kosterlitz-Thouless-like critical phase for the charge degrees of freedom in the intermediate-temperature regime between the charge-ordered and disordered phases in two-dimensional systems with competing short-range Coulomb repulsion.
Strongly Correlated Electrons Materials Science Statistical Mechanics
no code implementations • 30 Dec 2017 • Mario Bijelic, Ryui Kaneko, Claudius Gros, Roser Valentí
We investigate the competition between charge-density-wave (CDW) states and a Coulomb interaction-driven topological Mott insulator (TMI) in the honeycomb extended Hubbard model.
Strongly Correlated Electrons
no code implementations • 24 May 2017 • Ryui Kaneko, Luca F. Tocchio, Roser Valentí, Federico Becca
Motivated by recent experimental suggestions of charge-order-driven ferroelectricity in organic charge-transfer salts, such as $\kappa$-(BEDT-TTF)$_2$Cu[N(CN)$_2$]Cl, we investigate magnetic and charge-ordered phases that emerge in an extended two-orbital Hubbard model on the anisotropic triangular lattice at $3/4$ filling.
Strongly Correlated Electrons Materials Science
1 code implementation • 21 Jun 2016 • Ryui Kaneko, Luca F. Tocchio, Roser Valentí, Claudius Gros
For this purpose we investigate the phase diagram of doped extended Hubbard models on two lattices: (i) the honeycomb lattice with on-site $U$ and nearest-neighbor $V$ Coulomb interactions at $3/4$ filling ($n=3/2$) and (ii) the triangular lattice with on-site $U$, nearest-neighbor $V$, and next-nearest-neighbor $V'$ Coulomb interactions at $3/8$ filling ($n=3/4$).
Strongly Correlated Electrons
1 code implementation • 29 Oct 2015 • Ryui Kaneko, Luca F. Tocchio, Roser Valentí, Federico Becca, Claudius Gros
We show that Jastrow-Slater wave functions, in which a density-density Jastrow factor is applied onto an uncorrelated fermionic state, may possess long-range order even when all symmetries are preserved in the wave function.
Strongly Correlated Electrons
no code implementations • 28 Oct 2014 • Satoshi Morita, Ryui Kaneko, Masatoshi Imada
Our results, however, do not fully exclude the possibility of a direct quantum transition between the staggered AF and VBC phases with a wide critical region and deconfined criticality.
Strongly Correlated Electrons
no code implementations • 1 Jul 2014 • Ryui Kaneko, Satoshi Morita, Masatoshi Imada
We numerically study the Heisenberg models on triangular lattices by extending it from the simplest equilateral lattice with only the nearest-neighbor exchange interaction.
Strongly Correlated Electrons
no code implementations • 25 Mar 2013 • Ryui Kaneko, Satoshi Morita, Masatoshi Imada
We revisit the accuracy of the variational Monte Carlo (VMC) method by taking an example of ground state properties for the one-dimensional Hubbard model.
Strongly Correlated Electrons
no code implementations • 14 Apr 2010 • Ryui Kaneko, Takahiro Misawa, Masatoshi Imada
Motivated by a recent experiment on volborthite, a typical spin-$1/2$ antiferromagnet with a kagom\'{e} lattice structure, we study the magnetization process of a classical Heisenberg model on a spatially distorted kagom\'{e} lattice using the Monte Carlo (MC) method.
Strongly Correlated Electrons
