Optimizing stimulated Raman adiabatic passage for leakage suppression via Pontryagin's maximum principle

Quantum Physics [Submitted on 10 Apr 2026] Optimizing stimulated Raman adiabatic passage for leakage suppression via Pontryagin's maximum principle Xiao-Yu Dong, Xi-Lai Wang, Wen-Long Ma The standard stimulated Raman adiabatic passage (STIRAP) protocol enables high-fidelity quantum state transfer in an ideal three-level system via adiabatic following of a dark state evolution. However, in practical systems with more energy levels, control pulses with finite spectral selectivity often couple the three-level subspace to the remaining subspace, introducing leakage that fundamentally limits the transfer performance. Here, we adopt a multilevel chain model for STIRAP that explicitly incorporates this leakage subspace. Using Pontryagin's maximum principle, we formulate a leakage-penalized quantum optimal control problem with the control pulses constrained to experimentally feasible Gaussian pulse families. We derive explicit gradients of the objective functional with respect to the pulse parameters, enabling efficient low-dimensional optimization that suppresses leakage while preserving the counterintuitive STIRAP pulse ordering. Numerical simulations for a superconducting transmon platform demonstrate that the optimized control pulses can significantly enhance the target-state transfer fidelity and provide enhanced robustness to amplitude miscalibration and detuning drifts. Comments: 17 pages, 5 figures Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2604.09196 [quant-ph]   (or arXiv:2604.09196v1 [quant-ph] for this version)   https://doi.org/10.48550/arXiv.2604.09196 Focus to learn more Submission history From: Xiaoyu Dong [view email] [v1] Fri, 10 Apr 2026 10:29:09 UTC (1,248 KB) Access Paper: HTML (experimental) view license Current browse context: quant-ph < prev   |   next > new | recent | 2026-04 References & Citations INSPIRE HEP NASA ADS Google Scholar Semantic Scholar Export BibTeX Citation Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer (What is the Explorer?) Connected Papers Toggle Connected Papers (What is Connected Papers?) Litmaps Toggle Litmaps (What is Litmaps?) scite.ai Toggle scite Smart Citations (What are Smart Citations?) Code, Data, Media Demos Related Papers About arXivLabs Which authors of this paper are endorsers? | Disable MathJax (What is MathJax?)