Rejection-free cluster Wang-Landau algorithm for hard-core lattice gases

Area of Science:

• Statistical Mechanics
• Computational Physics
• Materials Science

Background:

• Hard-core lattice gases are crucial models in statistical mechanics, but simulating their low-entropy states is computationally challenging.
• Existing simulation methods struggle with large excluded volumes and system sizes, limiting accurate density of states calculations.

Purpose of the Study:

• To introduce a new, rejection-free, flat histogram cluster algorithm for efficiently determining the density of states in hard-core lattice gases.
• To demonstrate the algorithm's capability in sampling difficult low-entropy states, even with significant particle exclusion.

Main Methods:

• The algorithm employs simultaneous evaporation and reoccupation of particles within a defined strip.
• It is implemented for hard-core lattice gases with k-nearest neighbor exclusions on square and cubic lattices.

Main Results:

• The algorithm successfully reproduced known results for k=1, 2, and 3 on both square and cubic lattices.
• It demonstrated superior accuracy and convergence compared to flat histogram algorithms using local or unbiased cluster moves, especially for larger systems.

Conclusions:

• The developed cluster algorithm offers a significant advancement for simulating hard-core lattice gases.
• It provides a more accurate and efficient method for calculating the density of states, particularly in challenging low-entropy regimes.