How to get the GW wavefunction

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jasonhan0710
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How to get the GW wavefunction

Post by jasonhan0710 » Tue Mar 02, 2021 3:42 am

Dear all,

I want to read the many-body wave functions and charge density. Specifically, I want to get the quasiparticle corrected wave function and substitute the wave function files in the 'prefix.save' directory. Which file should I read and how to transfer it into Quantum-ESPRESSO format?

Best regards,
Jason
Jason Han

Assistant Professor
Department of Physics
National University of Defense Technology
Hunan, China

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Daniele Varsano
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Re: How to get the GW wavefunction

Post by Daniele Varsano » Tue Mar 02, 2021 9:24 am

Dear Jason,
in order to have GW wavefunction a sort of self-consistency is needed, at the moment yambo calculate G0W0 or eigenvalue self-consistent GW which is a diagonal approximation so the wfs are not changed. There is the possibility to perform a coshex self-consistency, but it is not properly tested so it is not distributed with the GPL release.
Best,
Daniele
Dr. Daniele Varsano
S3-CNR Institute of Nanoscience and MaX Center, Italy
MaX - Materials design at the Exascale
http://www.nano.cnr.it
http://www.max-centre.eu/

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jasonhan0710
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Re: How to get the GW wavefunction

Post by jasonhan0710 » Tue Mar 09, 2021 2:59 am

Dear Daniele,

Thanks for your reply.
in order to have GW wavefunction a sort of self-consistency is needed
What kind of self-consistency do we need? Can we just get the self-energy with Yambo and put it into the SCF calculation, just like a DFT+U calculation? Do you think it's a reasonable approximation?
There is the possibility to perform a coshex self-consistency
If possible, would you please send me a copy of this version?

Also, I have another question. What is the output in "ndb.QP" file? How to read it and get the quasiparticle energy?

Best regards,
Jason
Jason Han

Assistant Professor
Department of Physics
National University of Defense Technology
Hunan, China

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Daniele Varsano
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Joined: Tue Mar 17, 2009 2:23 pm
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Re: How to get the GW wavefunction

Post by Daniele Varsano » Tue Mar 09, 2021 9:04 am

Daer Jason,
What kind of self-consistency do we need? Can we just get the self-energy with Yambo and put it into the SCF calculation, just like a DFT+U calculation? Do you think it's a reasonable approximation?
Self energy are non-local object and QE is not meant to do that. If you want to perform a quasi-particle self consistent calculation you may have a look to the works of of Mark van Schilfgaarde: M van Schilfgaarde, T Kotani, S Faleev Physical review letters 96 (22), 226402

this is implemented in the quest all code: https://www.questaal.org/get/

Anyway, are you sure you need to perform quasi-particle self consistent calculations?
If possible, would you please send me a copy of this version?
This is a develop version and it s not yet ready to be distributed.
Also, I have another question. What is the output in "ndb.QP" file? How to read it and get the quasiparticle energy?
This is the yambo database in netcdf format containing the quasi-particle corrections. QP energy can be read both in the report and in the output o.qp of the calculation.

Best,
Daniele
Dr. Daniele Varsano
S3-CNR Institute of Nanoscience and MaX Center, Italy
MaX - Materials design at the Exascale
http://www.nano.cnr.it
http://www.max-centre.eu/

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