RydState - A Rydberg State Calculator

The RydState software calculates properties of Rydberg states. We especially focus on the calculation of the radial wavefunction of Rydberg states via the Numerov method. The software can be installed via pip (requires Python >= 3.10):

pip install rydstate

To install the latest development version from github, use:

pip install git+https://github.com/pairinteraction/rydstate

How to Cite

This package relies on quantum defects provided by the community. Consider citing relevant publications for your atomic species.

Click to expand for quantum defect references

Element	Model	Identifier	References
H	SQDT	`H`	Schrödinger equation for hydrogen
Li	SQDT	`Li`	10.1017/CBO9780511524530 (1994) 10.1103/PhysRevA.34.2889 (1986)
Na	SQDT	`Na`	10.1088/0953-4075/30/10/009 (1997) 10.1070/QE1995v025n09ABEH000501 (1995) 10.1103/PhysRevA.45.4720 (1992)
K	SQDT	`K`	10.1088/0031-8949/27/4/012 (1983) 10.1016/0030-4018(81)90225-X (1981)
Rb	SQDT	`Rb`	10.1103/PhysRevA.83.052515 (2011) 10.1103/PhysRevA.74.054502 (2006) 10.1103/PhysRevA.74.062712 (2006) 10.1103/PhysRevA.67.052502 (2003)
Cs	SQDT	`Cs`	10.1103/PhysRevA.93.013424 (2016) 10.1103/PhysRevA.35.4650 (1987) 10.1103/PhysRevA.26.2733 (1982)
Sr88	SQDT	`Sr88_sqdt`	10.1103/PhysRevA.108.022815 (2023) 10.17169/refubium-34581 (2022) 10.1016/j.cpc.2020.107814 (2021)
Sr87	MQDT	`Sr87_mqdt`	10.1088/1361-6455/ab4c22 (2019)
Sr88	MQDT	`Sr88_mqdt`	10.1088/1361-6455/ab4c22 (2019)
Yb171	MQDT	`Yb171_mqdt`	10.1103/PhysRevX.15.011009 (2025) 10.1103/mzsv-rckx (2025)
Yb173	MQDT	`Yb173_mqdt`	MQDT model formulated by Frederic Hummel
Yb174	MQDT	`Yb174_mqdt`	10.1103/PhysRevX.15.011009 (2025) 10.1103/mzsv-rckx (2025)

Documentation

User Guide

Tutorials - Examples of how to use the RydState library.
API Reference - Documentation of classes and functions of the RydState Python library.

Contributors

This software is currently maintained by:

Johannes Mögerle

The following people have made significant contributions:

Frederic Hummel - Supported the development of the MQDT implementation. Author of the MQDT.jl Julia package, on which this package’s Python implementation of the MQDT calculations is based.
Sebastian Weber - Provided substantial input on the physics and software architecture of this package.

We warmly welcome new contributions!

License

The rydstate software is licensed under LGPL v3. For more information, see LICENSE.txt.