A First-principles Computational Framework for Quantum Decoherence in Complex Diamond Spin Environments --> Quantum Physics arXiv:2608.02846 (quant-ph) [Submitted on 3 Aug 2026] Title:A First-principles Computational Framework for Quantum Decoherence in Complex Diamond Spin Environments Authors:Huijin Park, Ha-young Jeong, Hyeonsu Kim, Christoph Findler, Fedor Jelezko, Sangwon Oh, Junghyun Lee, Giulia Galli, Hosung Seo View a PDF of the paper titled A First-principles Computational Framework for Quantum Decoherence in Complex Diamond Spin Environments, by Huijin Park and 8 other authors View PDF Abstract:Quantum decoherence induced by defects remains a major limitation for solid-state quantum technologies, yet predicting decoherence in realistic materials remains computationally challenging. Complex defect populations are often approximated as homogeneous spin baths, obscuring the role of defect-specific electronic structure and spin dynamics. Here, we develop a predictive framework for decoherence in diamond by combining first-principles electronic-structure calculations, quantum many-body spin-bath simulations, and experimental validation. The framework incorporates defect-resolved spin Hamiltonians and heterogeneous spin baths containing multiple paramagnetic defect species. Using diamond nitrogen-vacancy ensembles as a model platform, we investigate mixed nitrogen-, vacancy-, and hydrogen-related defect environments. We show that decoherence depends not only on defect density but also on defect identity and bath composition, whose distinct electronic structures, hyperfine interactions, and spin dynamics produce different coherence behavior. Heterogeneous defect populations can either suppress or enhance decoherence, producing trends unexplained by homogeneous-bath models. Magnetic-field-dependent Hahn-echo measurements on samples with different defect concentrations validate the framework. The calculations reproduce the observed coherence times and stretched-exponential decay behavior across a broad magnetic-field range and identify vacancy-related defects as crit
