2025/10/31 by Hao Fang, Fang, Hao, Jing Chi +9
Physics and Astronomy · #Atomic and Molecular Physics #Quantum, superfluid, helium dynamics #Cold Atom Physics and Bose-Einstein Condensates
paper · pdf · doi:10.48550/arxiv.2510.27405
High-precision measurements of the fine-structure splittings in helium high Rydberg states have been reported, yet corresponding ab initio benchmarks for direct comparison remain unavailable. In this work, we extend the correlated B-spline basis function (C-BSBF) method to calculate the fine-structure splittings of high Rydberg states in 4He. The calculations include the mα4- and mα5-order contributions, the singlet-triplet mixing effect, and estimated spin-dependent mα6-order corrections obtained using a 1/n3 scaling approximation. High-precision ab initio results are obtained for principal quantum numbers n=24-37 with kilohertz-level accuracy and further extended to n=45-51 by extrapolation and fitting. The theoretical results show excellent agreement with quantum-defect theory (QDT) predictions and allow direct comparison with experimental measurements. Additionally, the discrepancy observed at n=34 is expected to be clarified with improved experimental precision.