# Difference between revisions of "ALPS 2 Tutorials:DMFT-02 Hybridization"

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# Tutorial 02: Hybridization Expansion CT-HYB / Tutorial 03: Interaction Expansion CT-INT

We will now reproduce the same result with a continuous-time Quantum Monte Carlo code: the Hybridization or CT-HYB code by Werner et al.. The parameters are the same, apart from the command for the solver:

SOLVER=Hybridization


You can find the parameter files (called *tsqrt2) in the directory tutorials/dmft-02-hybridization in the examples.

After running these simulations compare the output to the Hirsch Fye results. To rerun a simulation, you can specify a starting solution by defining G0OMEGA_INPUT, e.g. copy G0omga_output to G0_omega_input, specify G0OMEGA_INPUT = G0_omega_input in the parameter file and rerun the code.

You will notice that the results are relatively noisy. The reason for that is that the expansion order at such high temperatures is very small, which renders the measurement procedure inefficient. You can improve statistics by increasing the total run time (MAX_TIME) or by running it on more than one CPU. For running it with MPI, try mpirun -np procs dmft parameter_file or consult the man page of your mpi installation.

It is also instructive to run these calculations with a CT-INT code. This code performs an expansion in the interaction (instead of the hybridization). The corresponding parameter files are very similar, you can find them in the directory tutorials/dmft-03-interaction.

Tutorial by Emanuel - Please don't hesitate to ask!