--- DOAJ_listed: '1' OA_place: publisher OA_type: gold PlanS_conform: '1' _id: '21747' abstract: - lang: eng text: Entanglement does not always require one particle per party. It was predicted some 30 years ago that a single photon traversing a beam splitter could violate a Bell inequality. Although initially debated, single-photon nonlocality was eventually demonstrated via homodyne measurements. Here, we present an alternate realization that avoids the complexity of homodyne measurements and potential loopholes in their implementation. We violate a Bell inequality by performing joint measurements on two copies of the same single-photon entangled state, where one photon acts as a phase reference for the other, making it self-referential. We observe CHSH parameters of 2.71 = 0.09 and 2.23 = 0.07, depending on the joint measurements implemented. This offers a perspective on single-photon nonlocality and a more accessible experimental route, potentially applicable to general mode-entangled states in diverse platforms. acknowledgement: European Union ERC (101071779 (GRAVITES)); European Union Horizon 2020 Research and Innovation Programme (899368 (EPIQUS)); European Union Horizon 2020 Research and Innovation Programme Marie Sklodowska-Curie (956071 (AppQInfo)); European Union HORIZON Europe Research and Innovation Programme (101135288 (EPIQUE)); FWF Austrian Science Fund (10.55776/COE1 (Quantum Science Austria), 10.55776/F71 (BeyondC), 10.55776/FG5 (Research Group 5)); United States Air Force Office of Scientific Research (FA9550-21-1-0355 (Q-Trust), FA8655-23-1-7063 (TIQI)). article_processing_charge: Yes article_type: original arxiv: 1 author: - first_name: Daniel full_name: Kun, Daniel last_name: Kun - first_name: Karl T full_name: Strömberg, Karl T id: 68011cd2-da32-11ee-a930-b2774c7aba5f last_name: Strömberg - first_name: Borivoje full_name: Dakić, Borivoje last_name: Dakić - first_name: Philip full_name: Walther, Philip last_name: Walther - first_name: Lee A. full_name: Rozema, Lee A. last_name: Rozema citation: ama: Kun D, Strömberg KT, Dakić B, Walther P, Rozema LA. Testing single-photon entanglement using self-referential measurements. Optica. 2026;13(4):745-751. doi:10.1364/OPTICA.586172 apa: Kun, D., Strömberg, K. T., Dakić, B., Walther, P., & Rozema, L. A. (2026). Testing single-photon entanglement using self-referential measurements. Optica. Optica Publishing Group. https://doi.org/10.1364/OPTICA.586172 chicago: Kun, Daniel, Karl T Strömberg, Borivoje Dakić, Philip Walther, and Lee A. Rozema. “Testing Single-Photon Entanglement Using Self-Referential Measurements.” Optica. Optica Publishing Group, 2026. https://doi.org/10.1364/OPTICA.586172. ieee: D. Kun, K. T. Strömberg, B. Dakić, P. Walther, and L. A. Rozema, “Testing single-photon entanglement using self-referential measurements,” Optica, vol. 13, no. 4. Optica Publishing Group, pp. 745–751, 2026. ista: Kun D, Strömberg KT, Dakić B, Walther P, Rozema LA. 2026. Testing single-photon entanglement using self-referential measurements. Optica. 13(4), 745–751. mla: Kun, Daniel, et al. “Testing Single-Photon Entanglement Using Self-Referential Measurements.” Optica, vol. 13, no. 4, Optica Publishing Group, 2026, pp. 745–51, doi:10.1364/OPTICA.586172. short: D. Kun, K.T. Strömberg, B. Dakić, P. Walther, L.A. Rozema, Optica 13 (2026) 745–751. date_created: 2026-04-19T22:07:44Z date_published: 2026-04-20T00:00:00Z date_updated: 2026-05-05T12:05:47Z day: '20' ddc: - '530' department: - _id: OnHo doi: 10.1364/OPTICA.586172 external_id: arxiv: - '2511.21819' file: - access_level: open_access checksum: f6e62a93f274e0c07197bf4e457eff31 content_type: application/pdf creator: dernst date_created: 2026-05-05T12:01:08Z date_updated: 2026-05-05T12:01:08Z file_id: '21799' file_name: 2026_Optica_Kun.pdf file_size: 858539 relation: main_file success: 1 file_date_updated: 2026-05-05T12:01:08Z has_accepted_license: '1' intvolume: ' 13' issue: '4' language: - iso: eng license: https://creativecommons.org/licenses/by/4.0/ month: '04' oa: 1 oa_version: Published Version page: 745-751 project: - _id: bdb108fd-d553-11ed-ba76-83dc74a9864f grant_number: F07105 name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration of Superconducting Quantum Circuits publication: Optica publication_identifier: eissn: - 2334-2536 publication_status: published publisher: Optica Publishing Group quality_controlled: '1' scopus_import: '1' status: public title: Testing single-photon entanglement using self-referential measurements tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 13 year: '2026' ... --- DOAJ_listed: '1' OA_place: publisher OA_type: gold _id: '21641' abstract: - lang: eng text: Spectral filters are widely used in sensing and communicating with light, such as for separating wavelength channels in communications or sensing the specific spectra of some object or material of interest. The filter function is, however, often fixed, and precise filtering can require precise manufacturing. We propose an approach to integrated optical spectral filtering that allows arbitrary programmability, can compensate automatically for imperfections in filter fabrication, allows multiple simultaneous and separately programmable filter functions on the same input, and can configure itself automatically to the problem of interest, for example, to filter or reject multiple arbitrarily chosen frequencies. The approach exploits splitting the input light into an array of multiple waveguides of different lengths that then feed a programmable interferometer array that can also self-configure. It can give a spectral response similar to arrayed waveguide gratings but offers many other filtering functions, as well as supporting other structures based on non-redundant arrays for precise spectral filtering. Simultaneous filtering also allows an automatic measurement of the temporal coherency matrix and physical separation into the Karhunen–Loève expansion of temporally partially coherent light fields. With this approach, a wide range of spectral operations can be controllably, automatically, and precisely performed by an integrated photonic device with simple programmability. article_processing_charge: No article_type: original author: - first_name: David A. B. full_name: Miller, David A. B. last_name: Miller - first_name: Charles full_name: Roques-Carmes, Charles id: e2e68fc9-6505-11ef-a541-eb4e72cc3e82 last_name: Roques-Carmes - first_name: Carson G. full_name: Valdez, Carson G. last_name: Valdez - first_name: Anne R. full_name: Kroo, Anne R. last_name: Kroo - first_name: Marek full_name: Vlk, Marek last_name: Vlk - first_name: Shanhui full_name: Fan, Shanhui last_name: Fan - first_name: Olav full_name: Solgaard, Olav last_name: Solgaard citation: ama: Miller DAB, Roques-Carmes C, Valdez CG, et al. Universal programmable and self-configuring optical filter. Optica. 2025;12(9):1417-1426. doi:10.1364/optica.557630 apa: Miller, D. A. B., Roques-Carmes, C., Valdez, C. G., Kroo, A. R., Vlk, M., Fan, S., & Solgaard, O. (2025). Universal programmable and self-configuring optical filter. Optica. Optica Publishing Group. https://doi.org/10.1364/optica.557630 chicago: Miller, David A. B., Charles Roques-Carmes, Carson G. Valdez, Anne R. Kroo, Marek Vlk, Shanhui Fan, and Olav Solgaard. “Universal Programmable and Self-Configuring Optical Filter.” Optica. Optica Publishing Group, 2025. https://doi.org/10.1364/optica.557630. ieee: D. A. B. Miller et al., “Universal programmable and self-configuring optical filter,” Optica, vol. 12, no. 9. Optica Publishing Group, pp. 1417–1426, 2025. ista: Miller DAB, Roques-Carmes C, Valdez CG, Kroo AR, Vlk M, Fan S, Solgaard O. 2025. Universal programmable and self-configuring optical filter. Optica. 12(9), 1417–1426. mla: Miller, David A. B., et al. “Universal Programmable and Self-Configuring Optical Filter.” Optica, vol. 12, no. 9, Optica Publishing Group, 2025, pp. 1417–26, doi:10.1364/optica.557630. short: D.A.B. Miller, C. Roques-Carmes, C.G. Valdez, A.R. Kroo, M. Vlk, S. Fan, O. Solgaard, Optica 12 (2025) 1417–1426. date_created: 2026-03-30T12:22:48Z date_published: 2025-08-27T00:00:00Z date_updated: 2026-04-27T07:04:51Z day: '27' ddc: - '530' doi: 10.1364/optica.557630 extern: '1' external_id: pmid: - '11385580' intvolume: ' 12' issue: '9' language: - iso: eng main_file_link: - open_access: '1' url: https://doi.org/10.1364/OPTICA.557630 month: '08' oa: 1 oa_version: Published Version page: 1417-1426 pmid: 1 publication: Optica publication_identifier: eissn: - 2334-2536 publication_status: published publisher: Optica Publishing Group quality_controlled: '1' scopus_import: '1' status: public title: Universal programmable and self-configuring optical filter tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 12 year: '2025' ... --- DOAJ_listed: '1' OA_place: publisher OA_type: gold _id: '21640' abstract: - lang: eng text: "Conventional computing architectures have no known efficient algorithms for combinatorial optimization tasks such\r\nas the Ising problem, which requires finding the ground state spin configuration of an arbitrary Ising graph. Physical\r\nIsing machines have recently been developed as an alternative to conventional exact and heuristic solvers; however,\r\nthese machines typically suffer from decreased ground state convergence probability or universality for high edge-\r\ndensity graphs or arbitrary graph weights, respectively. We experimentally demonstrate a proof-of-principle integrated\r\nnanophotonic recurrent Ising sampler (INPRIS), using a hybrid scheme combining electronics and silicon-on-insulator\r\nphotonics, that is capable of converging to the ground state of various four-spin graphs with high probability. The\r\nINPRIS results indicate that noise may be used as a resource to speed up the ground state search and to explore larger\r\nregions of the phase space, thus allowing one to probe noise-dependent physical observables. Since the recurrent pho-\r\ntonic transformation that our machine imparts is a fixed function of the graph problem and therefore compatible with\r\noptoelectronic architectures that support GHz clock rates (such as passive or non-volatile photonic circuits that do not\r\nrequire reprogramming at each iteration), this work suggests the potential for future systems that could achieve orders-\r\nof-magnitude speedups in exploring the solution space of combinatorially hard problems. " article_processing_charge: No article_type: original author: - first_name: Mihika full_name: Prabhu, Mihika last_name: Prabhu - first_name: Charles full_name: Roques-Carmes, Charles id: e2e68fc9-6505-11ef-a541-eb4e72cc3e82 last_name: Roques-Carmes - first_name: Yichen full_name: Shen, Yichen last_name: Shen - first_name: Nicholas full_name: Harris, Nicholas last_name: Harris - first_name: Li full_name: Jing, Li last_name: Jing - first_name: Jacques full_name: Carolan, Jacques last_name: Carolan - first_name: Ryan full_name: Hamerly, Ryan last_name: Hamerly - first_name: Tom full_name: Baehr-Jones, Tom last_name: Baehr-Jones - first_name: Michael full_name: Hochberg, Michael last_name: Hochberg - first_name: Vladimir full_name: Čeperić, Vladimir last_name: Čeperić - first_name: John D. full_name: Joannopoulos, John D. last_name: Joannopoulos - first_name: Dirk R. full_name: Englund, Dirk R. last_name: Englund - first_name: Marin full_name: Soljačić, Marin last_name: Soljačić citation: ama: Prabhu M, Roques-Carmes C, Shen Y, et al. Accelerating recurrent Ising machines in photonic integrated circuits. Optica. 2020;7(5):551-558. doi:10.1364/optica.386613 apa: Prabhu, M., Roques-Carmes, C., Shen, Y., Harris, N., Jing, L., Carolan, J., … Soljačić, M. (2020). Accelerating recurrent Ising machines in photonic integrated circuits. Optica. Optica Publishing Group. https://doi.org/10.1364/optica.386613 chicago: Prabhu, Mihika, Charles Roques-Carmes, Yichen Shen, Nicholas Harris, Li Jing, Jacques Carolan, Ryan Hamerly, et al. “Accelerating Recurrent Ising Machines in Photonic Integrated Circuits.” Optica. Optica Publishing Group, 2020. https://doi.org/10.1364/optica.386613. ieee: M. Prabhu et al., “Accelerating recurrent Ising machines in photonic integrated circuits,” Optica, vol. 7, no. 5. Optica Publishing Group, pp. 551–558, 2020. ista: Prabhu M, Roques-Carmes C, Shen Y, Harris N, Jing L, Carolan J, Hamerly R, Baehr-Jones T, Hochberg M, Čeperić V, Joannopoulos JD, Englund DR, Soljačić M. 2020. Accelerating recurrent Ising machines in photonic integrated circuits. Optica. 7(5), 551–558. mla: Prabhu, Mihika, et al. “Accelerating Recurrent Ising Machines in Photonic Integrated Circuits.” Optica, vol. 7, no. 5, Optica Publishing Group, 2020, pp. 551–58, doi:10.1364/optica.386613. short: M. Prabhu, C. Roques-Carmes, Y. Shen, N. Harris, L. Jing, J. Carolan, R. Hamerly, T. Baehr-Jones, M. Hochberg, V. Čeperić, J.D. Joannopoulos, D.R. Englund, M. Soljačić, Optica 7 (2020) 551–558. date_created: 2026-03-30T12:22:48Z date_published: 2020-05-18T00:00:00Z date_updated: 2026-04-27T07:06:04Z day: '18' ddc: - '530' doi: 10.1364/optica.386613 extern: '1' intvolume: ' 7' issue: '5' language: - iso: eng main_file_link: - open_access: '1' url: https://doi.org/10.1364/OPTICA.386613 month: '05' oa: 1 oa_version: Published Version page: 551-558 publication: Optica publication_identifier: eissn: - 2334-2536 publication_status: published publisher: Optica Publishing Group quality_controlled: '1' scopus_import: '1' status: public title: Accelerating recurrent Ising machines in photonic integrated circuits tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 7 year: '2020' ...