Wave--particle duality is a hallmark of quantum mechanics. For bosonic systems, there exists a continuum of intermediate states bridging wave-like Schr\"odinger cat states and particle-like Fock states. Such states have recently been recognized as valuable resources for enhancing fault-tolerant quantum computation (FTQC) with propagating light. Here we experimentally demonstrate tunable generation of these intermediate states by employing generalized photon subtraction (GPS). By detecting up to three photons from squeezed-light sources with a photon-number-resolving detector, we continuously control the balance between wave- and particle-like features. This approach allows us to construct a spectral family of quantum states with high generation rates, optimized according to the required fault-tolerance threshold. Our results establish GPS as a versatile toolbox for tailoring non-Gaussian resources, opening a pathway to efficient Gottesman--Kitaev--Preskill (GKP) qubit generation and addressing a central bottleneck in optical quantum computing.
@article{arxiv.2602.21629,
title = {Tuning Wave-Particle Duality of Quantum Light by Generalized Photon Subtraction},
author = {Kan Takase and Mamoru Endo and Fumiya Hanamura and Kazuki Hirota and Masahiro Yabuno and Hirotaka Terai and Shigehito Miki and Takahiro Kashiwazaki and Asuka Inoue and Takeshi Umeki and Petr Marek and Radim Filip and Warit Asavanant and Akira Furusawa},
journal= {arXiv preprint arXiv:2602.21629},
year = {2026}
}