{"id":16151297,"url":"https://github.com/terrygeng/rate-equation","last_synced_at":"2026-04-29T01:34:05.035Z","repository":{"id":181699179,"uuid":"667158961","full_name":"TerryGeng/rate-equation","owner":"TerryGeng","description":"Rate equation model for simulating the atomic population evolution under external laser fields, implemented in python.","archived":false,"fork":false,"pushed_at":"2023-07-18T14:33:43.000Z","size":303,"stargazers_count":1,"open_issues_count":0,"forks_count":0,"subscribers_count":1,"default_branch":"master","last_synced_at":"2025-02-13T05:15:52.190Z","etag":null,"topics":["atomic","physics","python","quantum","simulation"],"latest_commit_sha":null,"homepage":"","language":"Jupyter Notebook","has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":null,"status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/TerryGeng.png","metadata":{"files":{"readme":"README.md","changelog":null,"contributing":null,"funding":null,"license":null,"code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":null,"support":null,"governance":null}},"created_at":"2023-07-16T20:43:50.000Z","updated_at":"2024-04-25T08:14:18.000Z","dependencies_parsed_at":"2023-07-16T23:06:47.848Z","dependency_job_id":"ba257f76-88ee-4b50-9e1f-69cfc06c26ee","html_url":"https://github.com/TerryGeng/rate-equation","commit_stats":{"total_commits":7,"total_committers":1,"mean_commits":7.0,"dds":0.0,"last_synced_commit":"93a5bd08735b317274844f1c7c1ea1399550b56f"},"previous_names":["terrygeng/rate-equation"],"tags_count":0,"template":false,"template_full_name":null,"repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/TerryGeng%2Frate-equation","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/TerryGeng%2Frate-equation/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/TerryGeng%2Frate-equation/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/TerryGeng%2Frate-equation/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/TerryGeng","download_url":"https://codeload.github.com/TerryGeng/rate-equation/tar.gz/refs/heads/master","host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":247563916,"owners_count":20958971,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2022-07-04T15:15:14.044Z","host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":["atomic","physics","python","quantum","simulation"],"created_at":"2024-10-10T00:55:46.986Z","updated_at":"2026-04-29T01:34:04.996Z","avatar_url":"https://github.com/TerryGeng.png","language":"Jupyter Notebook","funding_links":[],"categories":[],"sub_categories":[],"readme":"# `rate_equation`: Rate equation model implemented in python\n\n![Figure: Ground state population vs. laser detuning, under given magnetic\nfield](./screenshot.png)\n\n_Figure: Ground state population vs. laser detuning, under given magnetic\nfield_\n\nThis package implements rate equation model in python. Rate equation model is\ncommonly used to simulate the evolution of atomic populations in different\nground states, under given external radiation (e.g. lasers) and magnetic\nfields.\n\nRate equation model assumes the time atoms spend in excited states is\nnegligible. That is, once excited, they immediately decay back to ground\nstates. Therefore, all coherence terms are discarded, leaving a set of\nequations describing the population transfer from one ground state to others.\nThis assumption is equivalent to assuming the timescale of interest is much\nlarger than the decay rate of studied energy levels, while the laser intensity\nis way below saturation intensity.\n\nA very good reference for this approach can be found at:\n[F. Atoneche and A. Kastberg, Simplified Approach for Quantitative Calculations\nof Optical Pumping, Eur. J. Phys. 38, 045703 (2017)](\nhttps://doi.org/10.1088/1361-6404/aa6e6f).\n\n## Features\n\nThis package\n\n- Takes hyperfine structure and transition strength as input, normalizes\n  transition strength properly and produces the rate equation matrix $G$.\n\n- Supports configurations that include multiple radiation fields with different\n  frequencies and polarizations.\n\n- Provides flexible ways of defining detuning terms (Zeeman shift and Doppler\n  shift).\n\n- Each part is [individually tested](./test/) against published results to ensure\n  correctness.\n\n## Limitations\n\n- This package is designed to work with hyperfine states $I, J, F, m_F$ as the\n  eigenstates of the unperturbed Hamiltonian. However, under strong magnetic\n  field, hyperfine states are no longer eigenstates and the system is better\n  described by $I, J, m_J, m_I$ (Paschen-Back effect). The only way to\n  correctly deal with this is to diagonalize the Hamiltonian under all magnetic\n  field configurations and use the acquired eigenstates to perform calculation.\n  This package is not well geared to achieve this.\n\n## Usage And Examples\n\nIn the [example.ipynb](./example.ipynb) IPython notebook, I reproduced all relevant\nfigures in [Atoneche (2017)](https://doi.org/10.1088/1361-6404/aa6e6f).\n\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fterrygeng%2Frate-equation","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fterrygeng%2Frate-equation","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fterrygeng%2Frate-equation/lists"}