{ "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": "275-20-070", "title": "The Reality of the Quantum State", "funding_scheme_id": 3054, "funding_scheme": "NWO-Talentprogramma Veni 2017 WOTRO ID", "department": "Sociale en Geesteswetenschappen", "sub_department": "WOTRO Science for Global Development", "start_date": "2018-01-16T00:00:00", "end_date": "2021-11-30T00:00:00", "reporting_year": 2017, "summary_nl": "Quantum mechanics is one of the most prominent theories of physics to date. However, since its conception, there have been disputes about the interpretation of its main object: the quantum state of a system. Are quantum states aspects of the world (ontic interpretation), or do they represent our knowledge about a system (epistemic interpretation)?\n\n\n\nFor some eighty years, this has been mainly a philosophical question. However, in 2012, Pusey, Barrett and Rudolph (PBR) showed that, given some intuitive assumptions, an epistemic interpretation is in conflict with quantum mechanical predictions. Specifically, their theorem demonstrates that, in any model that is able to reproduce the predictions of quantum mechanics, and in which states give a direct description of reality, the quantum state must be part of this description of reality. Obviously, such a result requires that the notion of an ontic interpretation of quantum states is formalized within the language of mathematics. In this project this step will be severely scrutinized to assess the precise philosophical import of the PBR theorem and other so-called ψ-ontology theorems. In addition, there are two sub-projects on the implications of ψ-ontology theorems.\n\n\n\nThe first concerns the implications for the quantum mechanical description of macroscopic systems. Quantum mechanics allows for the possibility of superposition states which, on an ontic interpretation, leads to the famous paradox of Schrödinger's cat. This sub-project explicates the possibilities for reconciling the quantum description of macroscopic systems with our every day experience.\n\n\n\nThe second focuses on the role of quantum states as generators for probability functions. Does an ontic interpretation of quantum states directly imply that these probabilities are also intrinsic properties of the world? And if not, what do ψ-ontology theorems tell us about the nature of quantum probabilities? These questions will be answered in the second sub-project.", "summary_en": "Quantum mechanics is one of the most prominent theories of physics to date. However, since its conception, there have been disputes about the interpretation of its main object: the quantum state of a system. Are quantum states aspects of the world (ontic interpretation), or do they represent our knowledge about a system (epistemic interpretation)?\n\n\n\nFor some eighty years, this has been mainly a philosophical question. However, in 2012, Pusey, Barrett and Rudolph (PBR) showed that, given some intuitive assumptions, an epistemic interpretation is in conflict with quantum mechanical predictions. Specifically, their theorem demonstrates that, in any model that is able to reproduce the predictions of quantum mechanics, and in which states give a direct description of reality, the quantum state must be part of this description of reality. Obviously, such a result requires that the notion of an ontic interpretation of quantum states is formalized within the language of mathematics. In this project this step will be severely scrutinized to assess the precise philosophical import of the PBR theorem and other so-called ψ-ontology theorems. In addition, there are two sub-projects on the implications of ψ-ontology theorems.\n\n\n\nThe first concerns the implications for the quantum mechanical description of macroscopic systems. Quantum mechanics allows for the possibility of superposition states which, on an ontic interpretation, leads to the famous paradox of Schrödinger's cat. This sub-project explicates the possibilities for reconciling the quantum description of macroscopic systems with our every day experience.\n\n\n\nThe second focuses on the role of quantum states as generators for probability functions. Does an ontic interpretation of quantum states directly imply that these probabilities are also intrinsic properties of the world? And if not, what do ψ-ontology theorems tell us about the nature of quantum probabilities? These questions will be answered in the second sub-project.", "award_amount": 237870, "grant_id": "https://doi.org/10.61686/GKVSY57559", "project_members": [ { "role": "Researcher", "member_id": 346533, "last_name": "Hermens", "degree_pre_nominal": "dr.", "initials": "R.", "first_name": "Ronnie", "organisation": "Universiteit Utrecht", "organisation_id": 15878, "ror": "https://ror.org/04pp8hn57", "active": false }, { "role": "Main Applicant", "member_id": 346533, "last_name": "Hermens", "degree_pre_nominal": "dr.", "initials": "R.", "first_name": "Ronnie", "organisation": "Rijksuniversiteit Groningen", "organisation_id": 7905, "ror": "https://ror.org/012p63287", "active": true }, { "role": "Project leader", "member_id": 346533, "last_name": "Hermens", "degree_pre_nominal": "dr.", "initials": "R.", "first_name": "Ronnie", "organisation": "Universiteit Utrecht", "organisation_id": 15878, "ror": "https://ror.org/04pp8hn57", "active": true } ], "products": [ { "title": "Bell-inequality violation and relativity of pre- and postselection", "year": 2021, "edition": "104", "start": 12201, "end": 12201, "type": "Wetenschappelijk artikel", "url_open_access": "https://doi.org/10.1103/PhysRevA.104.012201", "journal_title": "Physical Review A", "authors": [ { "last_name": "Bacciagaluppi", "initials": "G", "role": "Auteur" }, { "last_name": "Hermens", "initials": "R", "role": "Auteur" } ] }, { "title": "An Operationalist Perspective on Setting Dependence", "year": 2019, "edition": "3", "start": 260, "end": 282, "type": "Wetenschappelijk artikel", "url_open_access": "10.1007/s10701-019-00243-5", "journal_title": "Foundations of Physics", "authors": [ { "last_name": "Hermens", "initials": "R", "role": "Auteur" } ] }, { "title": "How Real are Quantum States in ?-ontic Models?", "year": 2021, "edition": "51", "start": 38, "end": 38, "type": "Wetenschappelijk artikel", "url_open_access": "10.1007/s10701-021-00448-7", "journal_title": "Foundations of Physics", "authors": [ { "last_name": "Hermens", "initials": "R", "role": "Auteur" } ] }, { "title": "Completely real? A Critical Note on the Claims by Colbeck and Renner", "year": 2020, "edition": "72", "start": 121, "end": 137, "type": "Wetenschappelijk artikel", "url_open_access": "10.1016/j.shpsb.2020.08.005", "journal_title": "Studies in History and Philosophy of Modern Physics", "authors": [ { "last_name": "Hermens", "initials": "R", "role": "Auteur" } ] }, { "title": "Book review - The Meaning of the Wave Function e In Search of the Ontology of Quantum Mechanics, Shan Gao. Cambridge University Press (2017)", "year": 2019, "edition": "65", "start": 145, "end": 147, "type": "Publicatie", "url_open_access": "10.1016/j.shpsb.2018.08.001", "journal_title": "Studies in History and Philosophy of Modern Physics", "authors": [ { "last_name": "Hermens", "initials": "R", "role": "Maker" } ] } ] } ] }