# Connector theory for reusing model results to determine materials properties

Title | Connector theory for reusing model results to determine materials properties |

Publication Type | Palaiseau Article |

Short Title | npj Computational Materials |

Acknowledgements | ERC, Marie Curie CIG, GENCI |

Vanzini, M, Aouina, A, Panholzer, M, Gatti, M, Reining, L | |

Year of Publication | 2022 |

Journal | npj Computational Materials |

Volume | 8 |

URL | https://doi.org/10.1038/s41524-022-00762-2 |

Pagination | 98 |

Abstract | The success of Density Functional Theory (DFT) is partly due to that of simple approximations, such as the Local Density Approximation (LDA), which uses results of a model, the homogeneous electron gas, to simulate exchange-correlation effects in real materials. We turn this intuitive approximation into a general and in principle exact theory by introducing the concept of a connector: a prescription how to use results of a model system in order to simulate a given quantity in a real system. In this framework, the LDA can be understood as one particular approximation for a connector that is designed to link the exchange-correlation potentials in the real material to that of the model. Formulating the in principle exact connector equations allows us to go beyond the LDA in a systematic way. Moreover, connector theory is not bound to DFT, and it suggests approximations also for other functionals and other observables. We explain why this very general approach is indeed a convenient starting point for approximations. We illustrate our purposes with simple but pertinent examples. |