P-SOET

This program runs the Projected Site-Occupation Embedding Theory on the 1D Hubbard model:

https://arxiv.org/abs/1902.05747

It is a projected version (using Schmidt decomposition) of Site-Occupation Embedding Theory, which articles can be find at:

https://arxiv.org/abs/1409.2326

https://arxiv.org/abs/1602.02547

https://arxiv.org/abs/1710.03125

https://arxiv.org/abs/1806.06057

Requirements

• Python 2.7 or higher
• LAPACK and BLAS libraries
• Intel fortran compiler (or make the appropriate change in the Makefile)
• For multiple impurity sites : Density Matrix Renormalization Group (Block-1.5 code https://sanshar.github.io/Block/overview.html) and its own requirements.

Installation

Clone the complete repository:

$ git clone https:/bsenjean/P-SOET.git

Build the code:

$ cd code/
$ vi Makefile

Change the Makefile according to your preferences. Change compiler, add FLAGS, and change the path to the librairies.

$ make

$ cd ../work_dir/
$ vi script.py

In script.py you will see two environment variable to set, PSOET_DIR and DMRG_code. Set those variables in your PATH before running the script:

$ export PSOET_DIR=/path/to/P-SOET/
$ export DMRG_code=/path/to/block-1.5.3/

In HPC Strasbourg:

$ export DMRG_code=/usr/local/quant/block-1.5.3/

Use

$ python script.py

In script.py, you have to specify the following:

• Number of sites
• Number of electrons
• On-site Coulomb repulsion U
• Nearest neighbor hopping integral t
• Number of impurity sites
• Approximation (either iBALDA, 2LBALDA or SIAMBALDA. Refer to https://arxiv.org/abs/1806.06057 for their meaning)
• The code_directory

You can also specify optionally:

• The number of renormalized states to keep in DMRG
• The number of maximum iterations
• The threshold for convergence
• The use of a global chemical potential (for now, only for a single impurity problem)

How to cite

Cite the following paper:

• B. Senjean. Projected site-occupation embedding theory. arXiv:1902.05747

We would be grateful if you could cite the following articles if you found this program useful:

• B. Senjean, M. Tsuchiizu, V. Robert, E. Fromager. Local density approximation in site occupation embedding theory. Mol. Phys., 115, 48 (2017).

• B. Senjean, N. Nakatani, M. Tsuchiizu, E. Fromager. Site-Occupation Embedding Theory using Bethe Ansatz Local Density Approximations. Phys. Rev. B, 97, 235105 (2018).

• B. Senjean, N. Nakatani, M. Tsuchiizu, E. Fromager. Multiple impurities and combined local density approximations in Site-Occupation Embedding Theory. Theor. Chem. Acc. 137: 169 (2018)