Pump and Probe

This tutorial works only with Yambo version > 5.2, that will be released soon.

In this tutorial we will show you how to setup two external fields in yambo_nl, to perform pump and probe simulation. At present this tutorial explain only how to run simulation and obtain the final polarization. We are working on python script to analyze results that will be make available soon.

We start from the AlAs wave-functions of the Real time approach to non-linear response tutorial and remove symmetries according to the Pump and Probe external fields as explained in the Prerequisites for Real Time propagation with Yambo.

In our example we choose direction [1,1,0] for the pump and [0,0,1] for the probe, the corresponding ypp.in file will be:

fixsyms                          # [R] Remove symmetries not consistent with an external perturbation
% Efield1
 1.000000 | 1.000000 | 0.000000 |        # First external Electric Field
%
% Efield2
 0.000000 | 0.000000 | 1.000000 |        # Additional external Electric Field
%
BField= 0.000000           T     # [MAG] Magnetic field modulus
Bpsi= 0.000000             deg   # [MAG] Magnetic field psi angle [degree]
Btheta= 0.000000           deg   # [MAG] Magnetic field theta angle [degree]
#RmAllSymm                     # Remove all symmetries 
RmTimeRev                     # Remove Time Reversal
#RmSpaceInv                    # Remove Spatial Inversion

then we generate the Pump&Probe input with the command yambo_nl -u p: