ALPS 2.1 Examples:Paramagnetic Metal

Paramagnetic metal and extrapolation errors

In this example we simulate the Hubbard model on the Bethe lattice with interaction $U=3D/\sqrt{2}$ at a temperature $\beta =32 \sqrt{2}/D$ using a paramagnetic self-consistency. We will calculate the self-energy and compare it to Fig. 15 in the DMFT review by Georges it et al., where Hirsch-Fye and Exact Diagonalizationr results are shown for the same system. In contrast to the Hirsch-Fye algorithm the two Continuous time Monte Carlo algorithms CT-HYB and CT-INT do not suffer from discretization errors and reproduce the ED-results.

The parameter files and python scripts are located in the directory tutorials/dmft-06-paramagnet in your ALPS install directory. You can run the simulations by executing

dmft parm_hyb

and

dmft parm_int

on the command line or by running the python scripts tutorial6a.py and tutorial6b.py with the vispython interpreter. At each DMFT iteration $i$ the self-energy is written to the file selfenergy_i. Plot the converged self-energy and compare your results to Fig. 15 in Georges it et al..