Abstract
We present a general strategy to extend quantum cluster algorithms for spin systems, such as the loop algorithm, to those with an arbitrary size of spins. The partition function of a high- spin system is generally represented by the path integral of a model with special boundary conditions in the imaginary-time direction. We introduce additional graphs for the boundary part and give the labeling probability explicitly, which completes the algorithm together with an existing algorithm. As a demonstration, we simulate the integer-spin antiferromagnetic Heisenberg chains. The magnitude of the first excitation gap is estimated to be 0.41048(6), 0.08917(4), and 0.01002(3) for , 2, and 3, respectively.
- Received 5 November 1999
DOI:https://doi.org/10.1103/PhysRevLett.87.047203
©2001 American Physical Society