Mixed eigenstates in spin-boson systems with one-photon and two-photon interactions

Quantum Physics [Submitted on 6 Apr 2026] Mixed eigenstates in spin-boson systems with one-photon and two-photon interactions David Villaseñor, Marko Robnik Spin-boson systems have attracted increasing attention as accessible experimental platforms and for their potential applications in designing quantum technologies. One characteristic of these systems is the transition from regular to completely chaotic behavior when certain control parameters are varied. However, the characterization of their mixed phase space has not been thoroughly explored. In this work, we investigate the properties of mixed eigenstates in spin-boson systems, comparing one-photon interactions with two-photon interactions. We propose a generalized definition of the phase-space overlap index to identify genuine mixed eigenstates. Our study highlights the fundamental differences that arise when two-photon processes are considered compared to one-photon processes and provides complementary evidence supporting the validity of the principle of uniform semiclassical condensation (PUSC) of quasiprobability functions in spin-boson systems. Comments: 21 pages, 13 figures Subjects: Quantum Physics (quant-ph); Statistical Mechanics (cond-mat.stat-mech); Chaotic Dynamics (nlin.CD) Cite as: arXiv:2604.05037 [quant-ph]   (or arXiv:2604.05037v1 [quant-ph] for this version)   https://doi.org/10.48550/arXiv.2604.05037 Focus to learn more Submission history From: David Villasenor [view email] [v1] Mon, 6 Apr 2026 18:00:05 UTC (11,353 KB) Access Paper: HTML (experimental) view license Current browse context: quant-ph < prev   |   next > new | recent | 2026-04 Change to browse by: cond-mat cond-mat.stat-mech nlin nlin.CD 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?)