The criticality of the (2+1)-dimensional XY model is investigated with the numerical diagonalization method. So far, it has been considered that the diagonalization method would not be very suitable...
The low-lying spectrum of the three-dimensional Ising model is investigated numerically; we made use of an equivalence between the excitation gap and the reciprocal correlation length. In the...
Multicriticality of the gonihedric model in 2+1 dimensions is investigated numerically. The gonihedric model is a fully frustrated Ising magnet with the finely tuned plaquette-type (four-body and...
Satoh, Katashi, Takahashi, Kazue, Kobayashi, Takuya, Yamamoto, Yuka, Nishiyama, Yoshihiro, Tanabe, Masatada
X-ray computed tomography (CT) has been used for diagnosis of pulmonary emphysema because it can reveal the morphology of low attenuation areas. Recently, 99mTc-Technegas imaging, one of several...
Finite-size scaling (FSS) of the five-dimensional (d=5) Ising model is investigated numerically. Because of the hyperscaling violation in d>4, FSS of the d=5 Ising model no longer obeys the...
Extending the parameter space of the three-dimensional (d=3) Ising model, we search for a regime of eliminated corrections to finite-size scaling. For that purpose, we consider a real-space...
A transfer-matrix simulation scheme for the three-dimensional (d=3) bond percolation is presented. Our scheme is based on Novotny's transfer-matrix formalism, which enables us to consider arbitrary...
A transfer-matrix simulation scheme for the three-dimensional (d=3) bond percolation is presented. Our scheme is based on Novotny's transfer-matrix formalism, which enables us to consider arbitrary...
Folding of the triangular lattice in a discrete three-dimensional space is studied numerically. Such ``discrete folding'' was introduced by Bowick and co-workers as a simplified version of the...
Based on Novotny's transfer-matrix method, we simulated the (stacked) triangular Ising antiferromagnet embedded in the space with the dimensions variable in the range 2 \le d \le 3. Our aim is to...
Based on Novotny's transfer-matrix method, we simulated the (stacked) triangular Ising antiferromagnet embedded in the space with the dimensions variable in the range 2
Three-dimensional Ising model with the plaquette-type (next-nearest-neighbor and four-spin) interactions is investigated numerically. This extended Ising model, the so-called gonihedric model, was...
A three-dimensional Ising model with the plaquette-type (next-nearest-neighbor and four-spin) interactions is investigated numerically. This extended Ising model, the so-called gonihedric model, was...
Folding of the triangular lattice in a discrete three-dimensional space is investigated numerically. Such ``discrete folding'' has come under through theoretical investigation, since Bowick and...
Folding of the triangular lattice in a discrete three-dimensional space is investigated numerically. Such "discrete folding" has come about through theoretical investigation, since Bowick and...
Effective bending moduli of a fluid membrane are investigated by means of the transfer-matrix method developed in our preceding paper. This method allows us to survey various statistical measures for...
Third Neighbor Correlators of Spin-1/2 Heisenberg Antiferromagnet (2003)
Sakai, Kazumitsu, Shiroishi, Masahiro, Nishiyama, Yoshihiro, Takahashi, Minoru
We exactly evaluate the third neighbor correlator and all the possible non-zero correlators of the spin-1/2 Heisenberg $XXX$ antiferromagnet in the ground state without magnetic field. All the...
It has been considered that the effective bending rigidity of fluid membranes should be reduced by thermal undulations. However, recent thorough investigation by Pinnow and Helfrich revealed...
An elastic string embedded between rigid walls is simulated by means of the density-matrix renormalization group. The string collides against the walls owing to the quantum-mechanical zero-point...
Strong-coupling expansion is performed for the lattice phi^4 model in 1+1 dimensions. Because the strong-coupling limit itself is not solvable, we employed numerical calculations so as to set up...
Emptiness Formation Probability for the One-Dimensional Isotropic XY Model (2001)
Shiroishi, Masahiro, Takahashi, Minoru, Nishiyama, Yoshihiro
We study a correlation function for the one-dimensional isotropic ${XY}$ model (${XX0}$ model), which is called the Emptiness Formation Probability (EFP). It is the probability of the formation of a...
Quantum-fluctuation-induced repelling interaction of quantum string between walls (2001)
Quantum string, which was brought into discussion recently as a model for the stripe phase in doped cuprates, is simulated by means of the density-matrix-renormalization-group method. String collides...
Nonequilibrium-current-induced corrections to the one-particle-correlation function in a wire (2000)
Electron gas in a wire connected to two terminals with potential drop is studied with the Schwinger-Keldysh formalism. Recent studies, where the current is enforced to flow with a Lagrange-multiplier...
Chiral order of the Josephson-junction ladder with half a flux quantum per plaquette is studied by means of the exact diagonalization method. We consider an extreme quantum limit where each...
Nonequilibrium electron transport through the Kondo impurity is investigated numerically for the system with twenty conduction-electron levels. The electron current under finite voltage drop is...
Ground state of the dissipative two-state system is investigated by means of the Lanczos diagonalization method. We adopted the Hilbert-space-reduction scheme proposed by Zhang, Jeckelmann and White...
Ground state of the two-dimensional hard-core-boson system in the presence of the quenched random chemical potential is investigated by means of the exact-diagonalization method for the system sizes...
Random-field-driven phase transitions in the ground state of the S=1 XXZ spin chain (1998)
Ground-state of the S=1 XXZ spin chain under the influence of the random magnetic field is studied by means of the exact-diagonalization method. The S=1/2 counterpart has been investigated...
Numerical Analysis of the Bond-Random Antiferromagnetic S=1 Heisenberg Chain (1997)
Ground state of the bond-random antiferromagnetic S=1 Heisenberg chain with the biquadratic interaction -\beta\sum_i(S_i S_i+1)^2 is investigated by means of the exact-diagonalization method and the...
Nishiyama, Yoshihiro, Suzuki, Masuo
The ground state and excitation spectra of the $S=1$ Heisenberg spin chain with hole hopping are investigated by means of the numerical-diagonalization method and by the help of the Zhang-Arovas...
Hidden Orders and RVB Formation of the Four-Leg Heisenberg Ladder Model (1995)
Nishiyama, Yoshihiro, Hatano, Naomichi, Suzuki, Masuo
The ground state of the four-chain Heisenberg ladder model is numerically investigated. Hidden-order correlations suitable for the system are introduced and calculated with an emphasis on the...
Scaling Theory of Antiferromagnetic Heisenberg Ladder Models (1995)
Hatano, Naomichi, Nishiyama, Yoshihiro
The $S=1/2$ antiferromagnetic Heisenberg model on multi-leg ladders is investigated. Criticality of the ground-state transition is explored by means of finite-size scaling. The ladders with an even...