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Pyqcm: An open-source Python library for quantum cluster methods
by Théo N. Dionne, Alexandre Foley, Moïse Rousseau, David Sénéchal
Submission summary
| Authors (as registered SciPost users): | David Sénéchal |
| Submission information | |
|---|---|
| Preprint Link: | https://arxiv.org/abs/2305.18643v2 (pdf) |
| Code repository: | https://bitbucket.org/dsenechQCM/qcm_wed.git |
| Date accepted: | Nov. 21, 2023 |
| Date submitted: | Oct. 17, 2023, 4:41 a.m. |
| Submitted by: | David Sénéchal |
| Submitted to: | SciPost Physics Codebases |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approaches: | Theoretical, Computational |
Abstract
Pyqcm is a Python/C++ library that implements a few quantum cluster methods with an exact diagonalization impurity solver. Quantum cluster methods are used in the study of strongly correlated electrons to provide an approximate solution to Hubbard-like models. The methods covered by this library are Cluster Perturbation Theory (CPT), the Variational Cluster Approach (VCA) and Cellular (or Cluster) Dynamical Mean Field Theory (CDMFT). The impurity solver (the technique used to compute the cluster's interacting Green function) is exact diagonalization from sparse matrices, using the Lanczos algorithm and variants thereof. The core library is written in C++ for performance, but the interface is in Python, for ease of use and inter-operability with the numerical Python ecosystem. The library is distributed under the GPL license.
Author comments upon resubmission
List of changes
• Fig. 1 has been modified as per the referees' suggestions.
• Fig. 2 has been modified to show G and M scheme periodizations, in 3D plots
• Comments on the hypothesis of existence/uniqueness of the self-energy functional (after Eq. 107) have been added.
• Sect. 5.8 has been added (issues with VCA) , with two new figures
• A short new section (7) has been inserted on the respective merits of CPT, VCA and CDMFT.
• Table 3 (performance tests) has been redone
• The paper is now compatible with version 2.2 of the pyqcm library
Published as SciPost Phys. Codebases 23-r2.2 (2023) , SciPost Phys. Codebases 23 (2023)
Reports on this Submission
Report
Sections 5.8 and 7 have been added and provide valuable additional information on the limitations and the pros and cons of the respective quantum cluster techniques. Together with the rest of the paper, this information will prove very useful for future users of the pyqcm code.
I strongly recommend the publication of the manuscript in SciPost Physics Codebases.
The source installation of the current version of the code (v. 2.2) worked fine on a compute cluster using an Intel compiler.
Minor remark:
-two typos that might need correction in the 3rd paragraph of the new section 7: "to me more" -> to be more ; "convergence issues grows" -> grow.