Orbital optimization of the electron-hole system

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Orbital optimization of the electron-hole system

Postby braulio » Wed Nov 23, 2016 4:19 pm

Hello Casino users,

I have tried to reproduce some results of the the article "Trion formation in a two-dimensional hole-doped electron gas" present in the list of papers published using the Casino program. I have done the optimization of the variational parameters to the backflow transformation and Jastrow factor, however, the variational function is not good enough yet. In such paper is mentioned that were performed optmization of the orbitals of the electron-hole system. I would like to do this. Nevertheless, our try to optmization of the plane-wave orbital for the 2d fluid (electron-hole) seems not to be working (or it is not yet implemented) or maybe I am doing something wrong. For the gaussian orbital it seems to be ok. Can somebody help me with this?
braulio
 
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Re: Orbital optimization of the electron-hole system

Postby Pablo_Lopez_Rios » Wed Nov 23, 2016 4:34 pm

Hi braulio,

I don't fully understand what you are trying to do, but there are publicly-available input/output files for the CASINO calculations reported in the paper you mention, as indicated in the acknowledgments, see http://dx.doi.org/10.17863/CAM.565 . These include optimized wave functions for the HEG and hole-in-HEG systems, as used in the paper. Perhaps you could have a look at these files for guidance?

Best,
Pablo
Hey there! I am using CASINO.
Pablo_Lopez_Rios
 
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Re: Orbital optimization of the electron-hole system

Postby braulio » Mon Nov 28, 2016 8:06 pm

Thanks for the advice.
braulio
 
Posts: 6
Joined: Wed Aug 21, 2013 11:32 am
Location: Instituto de Física de São Carlos-USP

Re: Orbital optimization of the electron-hole system

Postby braulio » Thu Dec 22, 2016 8:39 pm

Dear Pablo
We would like to have your helping to understand what's going on with my QMC calculations for the hole-doped electron gas system using the CASINO code (latest version ). First of all, I would like to reproduce your data provided on http://dx.doi.org/10.17863/CAM.565 . Using exactly your inputs our VMC results agree with your results. However, for the DMC calculations when using the Mahan orbital we are getting different results, i.e., the DMC energy increases rather than lower in comparison with VMC. Please, could you take look at the attached files.

Thank you very much.
Attachments
dmc.tar.gz
(3.43 MiB) Downloaded 120 times
vmc.tar.gz
(1.89 MiB) Downloaded 121 times
braulio
 
Posts: 6
Joined: Wed Aug 21, 2013 11:32 am
Location: Instituto de Física de São Carlos-USP

Re: Orbital optimization of the electron-hole system

Postby Pablo_Lopez_Rios » Thu Dec 22, 2016 10:23 pm

Hi Braulio,

Try re-running your DMC calculation starting with as many VMC configurations as the target DMC population, i.e., set vmc_nstep and vmc_nconfig_write to 1024 rather than 128.

Best,
Pablo
Hey there! I am using CASINO.
Pablo_Lopez_Rios
 
Posts: 42
Joined: Thu Jan 30, 2014 1:25 am

Re: Orbital optimization of the electron-hole system

Postby braulio » Fri Dec 23, 2016 12:19 pm

Hi Pablo

We believe that it is not the case. We have made several tests with different number of walkers without any sucesss (when we use Mahan orbital). For plane wave it seems ok. Could you make a short run test with your imputs using latest casino version considering mahan orbital ?
braulio
 
Posts: 6
Joined: Wed Aug 21, 2013 11:32 am
Location: Instituto de Física de São Carlos-USP


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