How to set dissipative effect in real time simulation

[Bramhachari Khamari]

Dear developers,
In order to treat dissipative effects beyond the linear regime, an imaginary term is added to the self energy. The additional term is given by the equation-34 of the given link (https://journals.aps.org/prb/abstract/1 ... .84.245110). The physical meaning of the input parameters as mentioned are i) lifetime of the
perturbed electronic population and ii) dephasing rate. Following are my questions related to the above

a) How to generate input tags to set the life time and dephasing rate.
b) In which part of the simulation I should include this.
c) I would also like to know the detailed procedure to include this effect as it is not mentioned in the tutorials.

Any help in this regard will be highly appreciated.

Regards,

[claudio]

Dear Bramhachari,

as empirical parameters you can set 0.1 eV for the de-phasing and 0.01 eV for the lifetime.
The de-phasing parameter you can get from the imaginary part of the self-energy, see for example here:

http://www.yambo-code.org/2021/01/03/ne ... -coupling/

while the life-time parameter has to be calculated with full non-equilibrium green's function theory,
at present not implemented in the GPL version.
However if you do not use very strong fields this parameter is not so important.

best
Claudio

[Bramhachari Khamari]

Dear Claudio Sir,
Thanks for the reply. I got the variable GDamping to set the lifetime. However, did not see any variable for the dephasing. Can you explain how to get it from the imaginary part of the self-energy.



Regards,

[claudio]

Dear Bramhachari

you can set the dephasing to 0.1 eV,
but if you want calculate it from electron-phonon coupling, you have to perform a full calculation as explained in the tutorial \

then generate the input of your real-time simulation adding the -V qp flag
and read the ndb.QP database generate from electron-phonon

GfnQPdb= "E W < SAVE/ndb.QP"

this will automatically set the dephasing from the imaginary part of the electron-phonon self-energy.

best
Claudio

[Bramhachari Khamari]

Dear Sir,
Thanks a lot for the reply.

Regards,