[{"status":"public","publication":"arXiv","type":"journal_article","language":[{"iso":"eng"}],"_id":"64877","project":[{"name":"TRR 142 - Polaronen-Einfluss auf die optischen Eigenschaften von Lithiumniobat (B07*)","_id":"168"},{"_id":"56","name":"TRR 142 - Project Area C"},{"name":"TRR 142 ; TP: C10: Erzeugung und Charakterisierung von Quantenlicht in nichtlinearen Systemen: Eine theoretische Analyse","_id":"174"}],"department":[{"_id":"15"},{"_id":"569"},{"_id":"170"},{"_id":"293"},{"_id":"35"},{"_id":"34"},{"_id":"61"},{"_id":"230"},{"_id":"623"},{"_id":"429"}],"user_id":"16199","year":"2026","citation":{"ama":"Taheri B, Kopylov D, Hammer M, Meier T, Förstner J, Sharapova PR. Gain-induced spectral non-degeneracy in type-II parametric down-conversion. <i>arXiv</i>. Published online 2026. doi:<a href=\"https://doi.org/10.48550/ARXIV.2603.01656\">10.48550/ARXIV.2603.01656</a>","ieee":"B. Taheri, D. Kopylov, M. Hammer, T. Meier, J. Förstner, and P. R. Sharapova, “Gain-induced spectral non-degeneracy in type-II parametric down-conversion,” <i>arXiv</i>, 2026, doi: <a href=\"https://doi.org/10.48550/ARXIV.2603.01656\">10.48550/ARXIV.2603.01656</a>.","chicago":"Taheri, Behnood, Denis Kopylov, Manfred Hammer, Torsten Meier, Jens Förstner, and Polina R. Sharapova. “Gain-Induced Spectral Non-Degeneracy in Type-II Parametric down-Conversion.” <i>ArXiv</i>, 2026. <a href=\"https://doi.org/10.48550/ARXIV.2603.01656\">https://doi.org/10.48550/ARXIV.2603.01656</a>.","short":"B. Taheri, D. Kopylov, M. Hammer, T. Meier, J. Förstner, P.R. Sharapova, ArXiv (2026).","bibtex":"@article{Taheri_Kopylov_Hammer_Meier_Förstner_Sharapova_2026, title={Gain-induced spectral non-degeneracy in type-II parametric down-conversion}, DOI={<a href=\"https://doi.org/10.48550/ARXIV.2603.01656\">10.48550/ARXIV.2603.01656</a>}, journal={arXiv}, author={Taheri, Behnood and Kopylov, Denis and Hammer, Manfred and Meier, Torsten and Förstner, Jens and Sharapova, Polina R.}, year={2026} }","mla":"Taheri, Behnood, et al. “Gain-Induced Spectral Non-Degeneracy in Type-II Parametric down-Conversion.” <i>ArXiv</i>, 2026, doi:<a href=\"https://doi.org/10.48550/ARXIV.2603.01656\">10.48550/ARXIV.2603.01656</a>.","apa":"Taheri, B., Kopylov, D., Hammer, M., Meier, T., Förstner, J., &#38; Sharapova, P. R. (2026). Gain-induced spectral non-degeneracy in type-II parametric down-conversion. <i>ArXiv</i>. <a href=\"https://doi.org/10.48550/ARXIV.2603.01656\">https://doi.org/10.48550/ARXIV.2603.01656</a>"},"title":"Gain-induced spectral non-degeneracy in type-II parametric down-conversion","doi":"10.48550/ARXIV.2603.01656","date_updated":"2026-03-10T15:41:18Z","date_created":"2026-03-10T15:37:22Z","author":[{"last_name":"Taheri","full_name":"Taheri, Behnood","first_name":"Behnood"},{"first_name":"Denis","id":"98502","full_name":"Kopylov, Denis","last_name":"Kopylov"},{"first_name":"Manfred","full_name":"Hammer, Manfred","id":"48077","last_name":"Hammer","orcid":"0000-0002-6331-9348"},{"full_name":"Meier, Torsten","id":"344","orcid":"0000-0001-8864-2072","last_name":"Meier","first_name":"Torsten"},{"first_name":"Jens","last_name":"Förstner","orcid":"0000-0001-7059-9862","full_name":"Förstner, Jens","id":"158"},{"last_name":"Sharapova","full_name":"Sharapova, Polina R.","id":"60286","first_name":"Polina R."}]},{"language":[{"iso":"eng"}],"external_id":{"arxiv":["2502.05123"]},"_id":"58544","department":[{"_id":"623"},{"_id":"15"},{"_id":"636"}],"user_id":"85279","abstract":[{"lang":"eng","text":"We introduce a new classification of multimode states with a fixed number of photons. This classification is based on the factorizability of homogeneous multivariate polynomials and is invariant under unitary transformations. The classes physically correspond to field excitations in terms of single and multiple photons, each of which being in an arbitrary irreducible superposition of quantized modes. We further show how the transitions between classes are rendered possible by photon addition, photon subtraction, and photon-projection nonlinearities. We explicitly put forward a design for a multilayer interferometer in which the states for different classes can be generated with state-of-the-art experimental techniques. Limitations of the proposed designs are analyzed using the introduced classification, providing a benchmark for the robustness of certain states and classes. "}],"status":"public","type":"preprint","title":"Multiphoton, multimode state classification for nonlinear optical circuits ","main_file_link":[{"open_access":"1","url":"https://doi.org/10.48550/arXiv.2502.05123"}],"oa":"1","date_updated":"2025-02-10T08:36:12Z","date_created":"2025-02-10T08:26:45Z","author":[{"last_name":"Kopylov","full_name":"Kopylov, Denis","id":"98502","first_name":"Denis"},{"id":"85279","full_name":"Offen, Christian","last_name":"Offen","orcid":"0000-0002-5940-8057","first_name":"Christian"},{"first_name":"Laura","full_name":"Ares, Laura","last_name":"Ares"},{"first_name":"Boris Edgar","last_name":"Wembe Moafo","id":"95394","full_name":"Wembe Moafo, Boris Edgar"},{"full_name":"Ober-Blöbaum, Sina","id":"16494","last_name":"Ober-Blöbaum","first_name":"Sina"},{"first_name":"Torsten","orcid":"0000-0001-8864-2072","last_name":"Meier","full_name":"Meier, Torsten","id":"344"},{"first_name":"Polina","last_name":"Sharapova","id":"60286","full_name":"Sharapova, Polina"},{"first_name":"Jan","id":"75127","full_name":"Sperling, Jan","orcid":"0000-0002-5844-3205","last_name":"Sperling"}],"year":"2025","citation":{"ama":"Kopylov D, Offen C, Ares L, et al. Multiphoton, multimode state classification for nonlinear optical circuits .","chicago":"Kopylov, Denis, Christian Offen, Laura Ares, Boris Edgar Wembe Moafo, Sina Ober-Blöbaum, Torsten Meier, Polina Sharapova, and Jan Sperling. “Multiphoton, Multimode State Classification for Nonlinear Optical Circuits ,” n.d.","ieee":"D. Kopylov <i>et al.</i>, “Multiphoton, multimode state classification for nonlinear optical circuits .” .","mla":"Kopylov, Denis, et al. <i>Multiphoton, Multimode State Classification for Nonlinear Optical Circuits </i>.","bibtex":"@article{Kopylov_Offen_Ares_Wembe Moafo_Ober-Blöbaum_Meier_Sharapova_Sperling, title={Multiphoton, multimode state classification for nonlinear optical circuits }, author={Kopylov, Denis and Offen, Christian and Ares, Laura and Wembe Moafo, Boris Edgar and Ober-Blöbaum, Sina and Meier, Torsten and Sharapova, Polina and Sperling, Jan} }","short":"D. Kopylov, C. Offen, L. Ares, B.E. Wembe Moafo, S. Ober-Blöbaum, T. Meier, P. Sharapova, J. Sperling, (n.d.).","apa":"Kopylov, D., Offen, C., Ares, L., Wembe Moafo, B. E., Ober-Blöbaum, S., Meier, T., Sharapova, P., &#38; Sperling, J. (n.d.). <i>Multiphoton, multimode state classification for nonlinear optical circuits </i>."},"publication_status":"submitted"},{"doi":"10.1063/5.0293116","title":"Bipartite entanglement extracted from multimode squeezed light generated in lossy waveguides","volume":2,"author":[{"first_name":"Denis","full_name":"Kopylov, Denis","id":"98502","last_name":"Kopylov"},{"full_name":"Meier, Torsten","id":"344","last_name":"Meier","orcid":"0000-0001-8864-2072","first_name":"Torsten"},{"last_name":"Sharapova","full_name":"Sharapova, Polina R.","id":"60286","first_name":"Polina R."}],"date_created":"2026-01-12T13:18:51Z","date_updated":"2026-01-12T13:23:36Z","publisher":"AIP Publishing","intvolume":"         2","citation":{"apa":"Kopylov, D., Meier, T., &#38; Sharapova, P. R. (2025). Bipartite entanglement extracted from multimode squeezed light generated in lossy waveguides. <i>APL Quantum</i>, <i>2</i>(4), Article 046116. <a href=\"https://doi.org/10.1063/5.0293116\">https://doi.org/10.1063/5.0293116</a>","short":"D. Kopylov, T. Meier, P.R. Sharapova, APL Quantum 2 (2025).","mla":"Kopylov, Denis, et al. “Bipartite Entanglement Extracted from Multimode Squeezed Light Generated in Lossy Waveguides.” <i>APL Quantum</i>, vol. 2, no. 4, 046116, AIP Publishing, 2025, doi:<a href=\"https://doi.org/10.1063/5.0293116\">10.1063/5.0293116</a>.","bibtex":"@article{Kopylov_Meier_Sharapova_2025, title={Bipartite entanglement extracted from multimode squeezed light generated in lossy waveguides}, volume={2}, DOI={<a href=\"https://doi.org/10.1063/5.0293116\">10.1063/5.0293116</a>}, number={4046116}, journal={APL Quantum}, publisher={AIP Publishing}, author={Kopylov, Denis and Meier, Torsten and Sharapova, Polina R.}, year={2025} }","chicago":"Kopylov, Denis, Torsten Meier, and Polina R. Sharapova. “Bipartite Entanglement Extracted from Multimode Squeezed Light Generated in Lossy Waveguides.” <i>APL Quantum</i> 2, no. 4 (2025). <a href=\"https://doi.org/10.1063/5.0293116\">https://doi.org/10.1063/5.0293116</a>.","ieee":"D. Kopylov, T. Meier, and P. R. Sharapova, “Bipartite entanglement extracted from multimode squeezed light generated in lossy waveguides,” <i>APL Quantum</i>, vol. 2, no. 4, Art. no. 046116, 2025, doi: <a href=\"https://doi.org/10.1063/5.0293116\">10.1063/5.0293116</a>.","ama":"Kopylov D, Meier T, Sharapova PR. Bipartite entanglement extracted from multimode squeezed light generated in lossy waveguides. <i>APL Quantum</i>. 2025;2(4). doi:<a href=\"https://doi.org/10.1063/5.0293116\">10.1063/5.0293116</a>"},"year":"2025","issue":"4","publication_identifier":{"issn":["2835-0103"]},"publication_status":"published","language":[{"iso":"eng"}],"article_number":"046116","department":[{"_id":"15"},{"_id":"569"},{"_id":"170"},{"_id":"293"},{"_id":"429"},{"_id":"230"},{"_id":"623"},{"_id":"35"}],"user_id":"16199","_id":"63562","project":[{"_id":"53","name":"TRR 142: Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten zu funktionellen Strukturen"},{"_id":"56","name":"TRR 142 - Project Area C"},{"_id":"174","name":"TRR 142 ; TP: C10: Erzeugung und Charakterisierung von Quantenlicht in nichtlinearen Systemen: Eine theoretische Analyse"},{"name":"PhoQC: Photonisches Quantencomputing","_id":"266"}],"status":"public","abstract":[{"text":"<jats:p>Entangled two-mode Gaussian states constitute an important building block for continuous variable quantum computing and communication protocols. In this work, we theoretically study two-mode bipartite states, which are extracted from multimode light generated via type-II parametric downconversion (PDC) in lossy waveguides. For these states, we demonstrate that the squeezing quantifies entanglement and we construct a measurement basis, which results in the maximal bipartite entanglement. We illustrate our findings by numerically solving the spatial master equation for PDC in a Markovian environment. The optimal measurement modes are compared with two widely used broadband bases: the Mercer–Wolf basis (the first-order coherence basis) and the Williamson–Euler basis.</jats:p>","lang":"eng"}],"publication":"APL Quantum","type":"journal_article"}]