scholarly journals Transition matrix cluster algorithms

2019 ◽  
Vol 30 (01) ◽  
pp. 1950004 ◽  
Author(s):  
David Yevick ◽  
Yong Hwan Lee
Keyword(s):  
Ising Model ◽  
Density Of States ◽  
Matrix Method ◽  
Transition Matrix ◽  
Detailed Balance ◽  
Accurate Method ◽  
Single Spin ◽  
Cluster Algorithms ◽  
Global Cluster ◽  
Model Transition

We demonstrate that a series of procedures for increasing the efficiency of transition matrix calculations can be realized by integrating the standard single-spin flip transition matrix method with global cluster flipping techniques. Our calculations employ a simple and accurate method based on detailed balance for computing the density of states from the Ising model transition matrix.

scholarly journals CLUSTER VS. SINGLE-SPIN ALGORITHMS—WHICH ARE MORE EFFICIENT?

1994 ◽  
Vol 05 (01) ◽  
pp. 1-14 ◽  
Author(s):  
N. ITO ◽  
G.A. KOHRING
Keyword(s):  
Ising Model ◽  
Critical Exponents ◽  
Cluster Algorithm ◽  
Computer Time ◽  
System Size ◽  
Statistical Accuracy ◽  
Single Spin ◽  
Cluster Algorithms ◽  
Vector Computers ◽  
Single Cluster

A comparison between single-cluster and single-spin algorithms is made for the Ising model in 2 and 3 dimensions. We compare the amount of computer time needed to achieve a given level of statistical accuracy, rather than the speed in terms of site updates per second or the dynamical critical exponents. Our main result is that the cluster algorithms become more efficient when the system size, Ld, exceeds, L~70–300 for d=2 and l~80–200 for d=3. The exact value of the crossover is dependent upon the computer being used. The lower end of the crossover range is typical of workstations while the higher end is typical of vector computers. Hence, even for workstations, the system sizes needed for efficient use of the cluster algorithm is relatively large.

Chemisorption of Ordered Overlayer on a Tight-Binding Metal Surface Two-Level Adsorbate

1982 ◽  
Vol 37 (10) ◽  
pp. 1147-1164
Author(s):  
K. Masuda
Keyword(s):  
Phase Shift ◽  
Transition Metal ◽  
Density Of States ◽  
Tight Binding ◽  
Electronic States ◽  
Bridge Site ◽  
Bonding Interaction ◽  
Model Transition ◽  
Adsorbate Structure ◽  
Shift Technique

The chemisorption of a two-level (at E1 and E2) adsorbate on the (001) surface of a tightbinding metal is investigated using the Green's function formalism and the phase shift technique. The adorbital density of states (DOS)ϱa(E) as well as the change in the electronic DOS Δϱ(E; E1, E2) due to chemisorption are calculated for the ordered overlayers with c(2 x 2), p(2 x 1), p(2 X 2), p(4 X 1) and c(4 X 2) structures. It is assumed that the chemisorbed species sit over the twofold bridge site of the (001) surface of the model transition metal and have a π-bonding interaction with the two substrate atoms. It is shown that the electronic states of the overlayers are very sensitive to the adsorbate coverage (0), adsorbate structure and adsorbate species (one level or two level adsorbates). Furthermore, it is shown that there are marked differences in the Δϱ(E) curves between the chemisorption of two level adsorbates Δϱ(E; E1, E2) and that of single level adsorbates Δϱ(E; E1) + Δϱ(E; E2) (simulating the changes in the electronic DOS during the dissociation of diatomic molecules).

TWO-DIMENSIONAL WANG–LANDAU SAMPLING OF AN ASYMMETRIC ISING MODEL

2009 ◽  
Vol 20 (09) ◽  
pp. 1357-1366 ◽  
Author(s):  
SHAN-HO TSAI ◽  
FUGAO WANG ◽  
D. P. LANDAU
Keyword(s):  
Phase Diagram ◽  
Ising Model ◽  
External Field ◽  
Density Of States ◽  
Triangular Lattice ◽  
Sampling Method ◽  
Two Dimensional ◽  
Theoretical Predictions ◽  
The Spectator ◽  
Three Body

We study the critical endpoint behavior of an asymmetric Ising model with two- and three-body interactions on a triangular lattice, in the presence of an external field. We use a two-dimensional Wang–Landau sampling method to determine the density of states for this model. An accurate density of states allowed us to map out the phase diagram accurately and observe a clear divergence of the curvature of the spectator phase boundary and of the derivative of the magnetization coexistence diameter near the critical endpoint, in agreement with previous theoretical predictions.

Sign in / Sign up

Export Citation Format

Share Document