Wave--particle transition and quantum Zeno effect in which-way experiments with a superconducting quantum processor

Quantum Physics [Submitted on 21 Apr 2026] Wave--particle transition and quantum Zeno effect in which-way experiments with a superconducting quantum processor Shiyu Wang, Zhiguang Yan, Clemens Gneiting, Rui Li, Franco Nori, Yasunobu Nakamura Wave--particle duality demonstrates the peculiar nature of quantum mechanics. In which-way experiments, depending on the measurement scheme, a particle exhibits either wave-like or particle-like properties, as summarized by Bohr's principle of complementarity. In this work, we implement Mach-Zehnder (MZ) interferometry on a two-dimensional (2D) superconducting quantum processor. With precise control of the which-way measurement strength, we demonstrate the transition of a photon from wave-like to particle-like behavior. Furthermore, by performing quantum state tomography on two qubits located in the two paths, we demonstrate that which-way measurements break the entanglement and coherence between the two paths and cause information leakage from the quantum system to the environment. To capture this behavior quantitatively, we derive complementarity relations between the entropy and the fringe visibility. By applying a continuous which-way measurement during the evolution, we also observe the quantum Zeno effect that partially obstructs the interferometer path, giving rise to nonmonotonic behavior of purity and von Neumann entropy. Our experiments provide a detailed characterization of the full interferometer dynamics, reveal the relation between wave--particle duality and quantum information, and demonstrate the potential of superconducting quantum processors for testing quantum foundations under high precision and controllability. Comments: 18 pages, 10 figures Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2604.19115 [quant-ph]   (or arXiv:2604.19115v1 [quant-ph] for this version)   https://doi.org/10.48550/arXiv.2604.19115 Focus to learn more Submission history From: Shiyu Wang [view email] [v1] Tue, 21 Apr 2026 05:53:37 UTC (4,043 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?)