{ "meta": { "api_type": "NWO Projects API", "version": "1.0.2", "licence": { "name": "CC0 1.0 Universal", "url": "https://creativecommons.org/publicdomain/zero/1.0", "description": "To the extent possible under law, all copyright and related or neighbouring rights have been waived worldwide to the data made available through this API." }, "documentation": "https://doi.org/10.5281/zenodo.14918287", "release_date": "2025-08-20T00:00:00", "funder": "https://doi.org/10.13039/501100003246", "ror_id": "https://ror.org/04jsz6e67", "date": "2026-11-05T00:00:00", "count": 1, "per_page": 100, "pages": 1, "page": 1 }, "projects": [ { "project_id": "639.021.231", "title": "Coalgebraic Models of Quantum Systems", "funding_scheme_id": 421, "funding_scheme": "NWO-Talentprogramma Veni 2012 EW", "department": "Exacte en Natuurwetenschappen", "sub_department": "Exacte Wetenschappen", "start_date": "2012-12-01T00:00:00", "end_date": "2015-12-01T00:00:00", "reporting_year": 2012, "summary_nl": "Quantum systems show great potential in effectively solving problems that are considered intractable on classic computers. Designing quantum algorithms, however, is generally recognised as a difficult task. One reason is that from the point of view of classical physics, quantum systems display counterintuitive behaviour. A system can be in several states at the same time, measurement outcomes are probabilistic and alter the system state, and different states can be indistinguishable. Yet, many of these aspects of quantum systems are quite familiar in the theory of state-based computing. Coalgebra is a mathematical theory of state-based systems which captures the notion of hidden state and provides generic definitions (parametric in the system type) of observable behaviour and bisimilarity. This parametricity separates system specific, combinatorial properties from conceptual, semantic concerns, and it allows for the uniform development of a wide range of reasoning tools such as coinductive methods and modal (fixed-point) logics which have been highly successful in the specification and verification of classical systems. This project aims to develop a semantic foundation for quantum computing by modelling quantum systems as coalgebras. The main challenge here is to capture the nature of quantum measurements and observations such that the resulting coalgebraic notion of state equivalence is the right one from the perspective of quantum computing, e.g., yielding the same density operator. Moreover, I will develop coalgebraic methods such as coinduction and coalgebraic modal logics to reason about quantum systems. In particular, I want to obtain a basis for the coalgebraic analysis of quantitative aspects of quantum systems such as measurement probabilities and trace distance. To achieve this, the modelling will use coalgebras over metric spaces and convex sets. Such investigations are themselves of coalgebraic interest.\n\n", "summary_en": "Quantum systems show great potential in effectively solving problems that are considered intractable on classic computers. Designing quantum algorithms, however, is generally recognised as a difficult task. One reason is that from the point of view of classical physics, quantum systems display counterintuitive behaviour. A system can be in several states at the same time, measurement outcomes are probabilistic and alter the system state, and different states can be indistinguishable. Yet, many of these aspects of quantum systems are quite familiar in the theory of state-based computing. Coalgebra is a mathematical theory of state-based systems which captures the notion of hidden state and provides generic definitions (parametric in the system type) of observable behaviour and bisimilarity. This parametricity separates system specific, combinatorial properties from conceptual, semantic concerns, and it allows for the uniform development of a wide range of reasoning tools such as coinductive methods and modal (fixed-point) logics which have been highly successful in the specification and verification of classical systems. This project aims to develop a semantic foundation for quantum computing by modelling quantum systems as coalgebras. The main challenge here is to capture the nature of quantum measurements and observations such that the resulting coalgebraic notion of state equivalence is the right one from the perspective of quantum computing, e.g., yielding the same density operator. Moreover, I will develop coalgebraic methods such as coinduction and coalgebraic modal logics to reason about quantum systems. In particular, I want to obtain a basis for the coalgebraic analysis of quantitative aspects of quantum systems such as measurement probabilities and trace distance. To achieve this, the modelling will use coalgebras over metric spaces and convex sets. Such investigations are themselves of coalgebraic interest.\n\n", "project_members": [ { "role": "Researcher", "member_id": 145545, "last_name": "Hansen", "degree_pre_nominal": "prof. dr.", "initials": "H.H.", "first_name": "Helle Hvid", "organisation": "Radboud Universiteit Nijmegen||Faculteit der Natuurwetenschappen, Wiskunde en Informatica||Computer Science", "organisation_id": 78685, "ror": "https://ror.org/016xsfp80", "active": false, "orcid": "https://orcid.org/0000-0001-7061-1219" }, { "role": "Project leader", "member_id": 145545, "last_name": "Hansen", "degree_pre_nominal": "prof. dr.", "initials": "H.H.", "first_name": "Helle Hvid", "organisation": "Technische Universiteit Delft||Faculteit Techniek, Bestuur en Management (TBM)||Department of Engineering Systems and Services||Energie en Industrie", "organisation_id": 78223, "ror": "https://ror.org/02e2c7k09", "active": false, "orcid": "https://orcid.org/0000-0001-7061-1219" }, { "role": "Researcher", "member_id": 145545, "last_name": "Hansen", "degree_pre_nominal": "prof. dr.", "initials": "H.H.", "first_name": "Helle Hvid", "organisation": "Technische Universiteit Delft||Faculteit Techniek, Bestuur en Management (TBM)||Department of Engineering Systems and Services||Energie en Industrie", "organisation_id": 78223, "ror": "https://ror.org/02e2c7k09", "active": false, "orcid": "https://orcid.org/0000-0001-7061-1219" }, { "role": "Main Applicant", "member_id": 145545, "last_name": "Hansen", "degree_pre_nominal": "prof. dr.", "initials": "H.H.", "first_name": "Helle Hvid", "organisation": "Technische Universiteit Delft||Faculteit Techniek, Bestuur en Management (TBM)||Department of Engineering Systems and Services||Energie en Industrie", "organisation_id": 78223, "ror": "https://ror.org/02e2c7k09", "active": true, "orcid": "https://orcid.org/0000-0001-7061-1219" } ], "products": [ { "title": "Algebra-Coalgebra Duality in Brzozowski's Minimization Algorithm", "year": 2014, "edition": "15", "start": 1, "end": 3, "type": "Wetenschappelijk artikel", "journal_title": "ACM Transactions on Computational Logic", "authors": [ { "last_name": "Bonchi", "initials": "F.", "role": "Auteur", "index_number": 1 }, { "last_name": "Bonsangue", "initials": "M. M.", "role": "Auteur", "index_number": 2 }, { "last_name": "Hansen", "initials": "H. H.", "role": "Auteur", "index_number": 3 }, { "last_name": "Panangaden", "initials": "P.", "role": "Auteur", "index_number": 4 }, { "last_name": "Rutten", "initials": "J.J.M.M", "role": "Auteur", "index_number": 5 }, { "last_name": "Silva", "initials": "A.", "role": "Auteur", "index_number": 6 } ] }, { "title": "A Final Coalgebra for k-Regular Sequences.", "year": 2014, "start": 363, "end": 383, "type": "Productbijdrage", "journal_title": "Springer", "authors": [ { "last_name": "Hansen", "initials": "H", "role": "Auteur", "index_number": 1 }, { "last_name": "Kupke", "initials": "C.", "role": "Auteur", "index_number": 2 }, { "last_name": "Rutten", "initials": "J.", "role": "Auteur", "index_number": 3 }, { "last_name": "Winter", "initials": "J.", "role": "Auteur", "index_number": 4 } ] }, { "title": "Strong Completeness for Iteration-Free Coalgebraic Dynamic Logics.\n8th IFIP TC 1/WG 2.2 International Conference, TCS 2014, Rome, Italy, September 1-3, 2014. Proceedings.", "sub_title": "8th IFIP TC 1/WG 2.2 International Conference, TCS 2014, Rome, Italy, September 1-3, 2014. Proceedings.", "year": 2014, "start": 281, "end": 295, "type": "Productbijdrage", "journal_title": "Springer", "authors": [ { "last_name": "Hansen", "initials": "H. H.", "role": "Auteur", "index_number": 1 }, { "last_name": "Kupke", "initials": "C.", "role": "Auteur", "index_number": 2 }, { "last_name": "Leal", "initials": "R. A.", "role": "Auteur", "index_number": 3 } ] }, { "title": "Stream Differential Equations: Specification Formats and Solution Methods.", "year": 2014, "type": "Overige Output", "authors": [ { "last_name": "Hansen", "initials": "H. H.", "role": "Maker", "index_number": 1 }, { "last_name": "Kupke", "initials": "C.", "role": "Maker", "index_number": 2 }, { "last_name": "Rutten", "initials": "J.J.M.M", "role": "Maker", "index_number": 3 } ] }, { "year": 2014, "start": 124, "end": 145, "type": "Productbijdrage", "journal_title": "Springer", "authors": [ { "last_name": "Basold", "initials": "H.", "role": "Auteur", "index_number": 1 }, { "last_name": "Bonsangue", "initials": "M.M.", "role": "Auteur", "index_number": 2 }, { "last_name": "Hansen", "initials": "H. H.", "role": "Auteur", "index_number": 3 }, { "last_name": "Rutten", "initials": "J.J.M.M", "role": "Auteur", "index_number": 4 } ] }, { "title": "A Coinductive Treatment of Infinitary Term Rewriting.", "year": 2013, "type": "Overige Output", "authors": [ { "last_name": "Endrullis", "initials": "J", "role": "Maker", "index_number": 1 }, { "last_name": "Hansen", "initials": "H", "role": "Maker", "index_number": 2 }, { "last_name": "Hendriks", "initials": "D.", "role": "Maker", "index_number": 3 }, { "last_name": "Polonsky", "initials": "A.", "role": "Maker", "index_number": 4 }, { "last_name": "Silva", "initials": "A.", "role": "Maker", "index_number": 5 } ] }, { "title": "Presenting Distributive Laws.\n5th International Conference, CALCO 2013, Warsaw, Poland, September 3-6, 2013. Proceedings.", "sub_title": "5th International Conference, CALCO 2013, Warsaw, Poland, September 3-6, 2013. Proceedings.", "year": 2013, "start": 95, "end": 109, "type": "Productbijdrage", "journal_title": "Springer", "authors": [ { "last_name": "Bonsangue", "initials": "M. M.", "role": "Auteur", "index_number": 1 }, { "last_name": "Hansen", "initials": "H. H.", "role": "Auteur", "index_number": 2 }, { "last_name": "Kurz", "initials": "A.", "role": "Auteur", "index_number": 3 }, { "last_name": "Rot", "initials": "J.", "role": "Auteur", "index_number": 4 } ] }, { "title": "Presenting Distributive Laws", "year": 2015, "edition": "11", "start": 1, "end": 23, "type": "Wetenschappelijk artikel", "url_open_access": "http://lmcs-online.org/ojs/viewarticle.php?id=1574&layout=abstract", "journal_title": "Logical Methods in Computer Science, volume 11, issue 3, paper 2", "authors": [ { "last_name": "Kurz", "initials": "A.", "role": "Auteur" }, { "last_name": "Hansen", "initials": "H.H.", "role": "Auteur" }, { "last_name": "Rot", "initials": "J.", "role": "Auteur" }, { "last_name": "Bonsangue", "initials": "M.", "role": "Auteur" } ] }, { "title": "SGF-Quantales and their Groupoids", "year": 2015, "type": "Overige Output", "authors": [ { "last_name": "Palmigiano", "initials": "A.", "role": "Maker" }, { "last_name": "Ossa", "initials": "C.", "role": "Maker" }, { "last_name": "Hansen", "initials": "H.H.", "role": "Maker" } ] }, { "title": "A Coinductive Treatment of Infinitary Term Rewriting and Equational Reasoning\nLeibniz International Proceedings in Informatics (LIPIcs)", "sub_title": "Leibniz International Proceedings in Informatics (LIPIcs)", "year": 2015, "edition": "1", "start": 143, "end": 159, "type": "Productbijdrage", "url_open_access": "http://drops.dagstuhl.de/opus/volltexte/2015/5194/", "journal_title": "Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik", "authors": [ { "last_name": "Polonsky", "initials": "A.", "role": "Auteur" }, { "last_name": "Silva", "initials": "A.", "role": "Auteur" }, { "last_name": "Hendriks", "initials": "D.", "role": "Auteur" }, { "last_name": "Hansen", "initials": "H.H.", "role": "Auteur" }, { "last_name": "Endrullis", "initials": "J.", "role": "Auteur" } ] }, { "title": "Weak Completeness of Coalgebraic Dynamic Logics\nElectronic Proceedings in Theoretical Computer Science vol. 191", "sub_title": "Electronic Proceedings in Theoretical Computer Science vol. 191", "year": 2015, "edition": "1", "start": 90, "end": 104, "type": "Productbijdrage", "url_open_access": "http://eptcs.web.cse.unsw.edu.au/paper.cgi?FICS2015.9", "journal_title": "Open Publishing Association", "authors": [ { "last_name": "Kupke", "initials": "C.", "role": "Auteur" }, { "last_name": "Hansen", "initials": "H. H.", "role": "Auteur" } ] }, { "title": "Newton Series, Coinductively\nvol. 9399 of Lecture Notes in Computer Science", "sub_title": "vol. 9399 of Lecture Notes in Computer Science", "year": 2015, "edition": "1", "start": 91, "end": 109, "type": "Productbijdrage", "journal_title": "Springer", "authors": [ { "last_name": "Basold", "initials": "H.", "role": "Auteur" }, { "last_name": "Hansen", "initials": "H.H.", "role": "Auteur" }, { "last_name": "Pin", "initials": "J.-E.", "role": "Auteur" }, { "last_name": "Rutten", "initials": "J.J.M.M.", "role": "Auteur" } ] } ] } ] }