Resolving Spin-Phonon Relaxation Pathways in Molecular Qubits via Regularized Regression
Abstract
Designing molecular qubits requires controlling the spin-lattice relaxation pathways that fundamentally limit the coherence time. For spin-1/2 molecular qubits, significant discrepancies remain between theoretical predictions and experimental measurements of spin-phonon relaxation pathways, with theory often overestimating the role of low-frequency vibrational modes. Here, we present an alternative first-principles approach augmented with regularized regression that identifies spin-phonon relaxation pathways in an automated fashion without ad hoc mode selection. Applied to Cu porphyrins spin-1/2 molecular qubits, the method successfully reproduces experimental trends in relaxation times and predicts the curvature in the relaxation-vs-temperature profile. The g-tensor time series reveal distinct system-specific autocorrelation functions and spectral-density profiles despite the qubits' structural similarity. Further, regression between g-tensor time series and mode-projected vibrational-amplitude time series obtained from molecular dynamics yields linear and bilinear mode coupling contributions to each g-tensor component. Because the method is based on atomic displacements sampled directly from molecular dynamics, it naturally incorporates anharmonic effects and does not require the harmonic approximation. This framework puts forward a regression-driven, mode-resolved, and coupling-order-separated spin-phonon analysis as a general strategy for predicting and engineering longer-lived molecular qubits.
Related
- Resolving Photochemical Reaction Pathways Using Field-Induced Surface Hopping Simulation of fs-EUV-TRPES: The Case of Furan
- Optimizing the Optimizer: Language Models Discover Faster Molecular Relaxation Algorithms
- Molecular Electrodynamic Relaxation in Dielectric and Plasmonic Cavities
- Resolving molecular biexcited states using classical leading-order triples corrections to quantum equation-of-motion UCCSD
- Angular Momentum Fluctuations Induced by Phonon-Rotation Coupling Govern Nuclear Spin Relaxation in a Molecular Rotator Phase
BibTeX
@misc{banerjee2026resolving,
title = {{Resolving Spin-Phonon Relaxation Pathways in Molecular Qubits via Regularized Regression}},
author = {Sayan Banerjee},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2608.27820},
eprint = {2608.27820},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.27820},
}
RIS
TY - UNPB
TI - Resolving Spin-Phonon Relaxation Pathways in Molecular Qubits via Regularized Regression
AU - Sayan Banerjee
PY - 2026
DA - 2026/08/28
PB - arXiv
DO - 10.48550/arxiv.2608.27820
UR - https://arxiv.org/abs/2608.27820
AB - Designing molecular qubits requires controlling the spin-lattice relaxation pathways that fundamentally limit the coherence time. For spin-1/2 molecular qubits, significant discrepancies remain between theoretical predictions and experimental measurements of spin-phonon relaxation pathways, with theory often overestimating the role of low-frequency vibrational modes. Here, we present an alternative first-principles approach augmented with regularized regression that identifies spin-phonon relaxation pathways in an automated fashion without ad hoc mode selection. Applied to Cu porphyrins spin-1/2 molecular qubits, the method successfully reproduces experimental trends in relaxation times and predicts the curvature in the relaxation-vs-temperature profile. The g-tensor time series reveal distinct system-specific autocorrelation functions and spectral-density profiles despite the qubits' structural similarity. Further, regression between g-tensor time series and mode-projected vibrational-amplitude time series obtained from molecular dynamics yields linear and bilinear mode coupling contributions to each g-tensor component. Because the method is based on atomic displacements sampled directly from molecular dynamics, it naturally incorporates anharmonic effects and does not require the harmonic approximation. This framework puts forward a regression-driven, mode-resolved, and coupling-order-separated spin-phonon analysis as a general strategy for predicting and engineering longer-lived molecular qubits.
ER -