2 research outputs found
Parallel loop cluster quantum Monte Carlo simulation of quantum magnets based on global union-find graph algorithm
A large-scale parallel loop cluster quantum Monte Carlo simulation is
presented. On 24,576 nodes of the K computer, one loop cluster Monte Carlo
update of the world-line configuration of the antiferromagnetic
Heisenberg chain with spins at inverse temperature is executed in about 8.62 seconds, in which global union-find
cluster identification on a graph of about 1.1 trillion vertices and edges is
performed. By combining the nonlocal global updates and the large-scale
parallelization, we have virtually achieved about -fold speed-up from
the conventional local update Monte Carlo simulation performed on a single
core. We have estimated successfully the antiferromagnetic correlation length
and the magnitude of the first excitation gap of the antiferromagnetic
Heisenberg chain for the first time as and , respectively.Comment: 16 pages, 9 figure
DSQSS: Discrete Space Quantum Systems Solver
The Discrete Space Quantum Systems Solver (DSQSS) is a program package for
solving quantum many-body problems defined on lattices. The DSQSS is based on
the quantum Monte Carlo method in Feynman's path integral representation and
covers a broad range of problems using flexible input files that define
arbitrary unit cells in arbitrary dimensions and arbitrary matrix elements
representing the interactions among an arbitrary number of degrees of freedom.
Finite temperature calculations of quantum spin and the Bose- Hubbard models
can be performed by specifying parameters such as the number of dimensions, the
lattice size, coupling constants, and temperature. The present paper details
the use of DSQSS and presents a number of applications thereof.Comment: 13 pages, 6 figures, accepted manuscrip