Guan - An Open Source Python Package

Guan is an open-source python package developed and maintained by https://www.guanjihuan.com/about (Ji-Huan Guan, 关济寰). With this package, you can calculate band structures, density of states, quantum transport and topological invariant of tight-binding models by invoking the functions you need. Other frequently used functions are also integrated in this package, such as file reading/writing, figure plotting, data processing.

The primary location of this package is on the current website https://py.guanjihuan.com. The latest version is “guan-0.0.168”, updated on April 25, 2023. You can install (upgrade) this package to the latest version by executing the following command in a terminal:

pip install --upgrade guan

Usage:

import guan

About this package:

The original motivation of this project is for self use. Based on this project, the frequent functions can be imported by “import guan” instead of repeated copies and pastes. You can also install and use this open-source package if some functions are helpful for you. If one function is not good enough, you can copy the Source Code and modify it. You can also feed back to guanjihuan@163.com. The modifications and supplements will be in the following updated version.
All realizations of this package are based on functions without any class, which are concise and convenient. The boring document is omitted and you have to read the Source Code for details if it is necessary. Nevertheless, you don’t have to be worried about the difficulty, because all functions are simple enough without too many prejudgments and the variable names are written commonly as far as possible for the easy reading.
Before the function calling in your project, you are recommended to briefly read the Source Code to know the specific formats of input and output about the function. Applying functions mechanically may cause errors. Notice that as the package is developed, the function names may be changed in the future version. Therefore, the latest API Reference is important and helpful.

License: GNU General Public License v3 (GPLv3).

Summary of API Reference:

basic functions
Fourier transform
Hamiltonian of finite size systems
Hamiltonian of models in the reciprocal space
band structures and wave functions
Green functions
density of states
quantum transport
topological invariant
read and write
plot figures
data processing
file processing
others

All files can be read here or downloaded from GitHub or Cloud.

Citation: There is no official paper related to this package temporarily, but you can cite one or all of the following papers instead which are the motivation of this project (e.g., calculating the scattering matrix), if this package is greatly helpful for your research.

Ji-Huan Guan, Yan-Yang Zhang, Si-Si Wang, Yan Yu, Yang Xia and Shu-Shen Li, Barrier Tunneling and Loop Polarization in Hopf Semimetals, Phys. Rev. B 102, 064203 (2020).
Ji-Huan Guan, Yan-Yang Zhang, Wei-Er Lu, Yang Xia and Shu-Shen Li, Barrier tunneling of the loop-nodal semimetal in the hyperhoneycomb lattice, J. Phys.: Condens. Matter 30, 185402 (2018).