ALPS 2 Tutorials:DWA-01 Revisiting MC05

Quantum phase transitions in the Bose-Hubbard model

As an example of the dwa QMC code we will study a quantum phase transition in the Bose-Hubbard mode.

Superfluid density in the Bose Hubbard model

Preparing and running the simulation from the command line

The parameter file parm1a sets up Monte Carlo simulations of the quantum Bose Hubbard model on a square lattice with 4x4 sites for a couple of hopping parameters (t=0.01, 0.02, ..., 0.1) using the dwa code.

 LATTICE="square lattice";
 L=4;
 
 MODEL="boson Hubbard";
 Nmax = 2;
 U    = 1.0;
 mu   = 0.5;
 
 T    = 0.1;
 
 SWEEPS=5000000;
 THERMALIZATION=100000;
 SKIP=5000;
 
 { t=0.01; }
 { t=0.02; }
 { t=0.03; }
 { t=0.04; }
 { t=0.05; }
 { t=0.06; }
 { t=0.07; }
 { t=0.08; }
 { t=0.09; }
 { t=0.1;  }

Using the standard sequence of commands you can run the simulation using the quantum dwa code

parameter2xml parm1a
dwa --Tmin 5 --write-xml parm1a.in.xml