{ "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": "740.018.017", "title": "New routes towards quantum gravity in the ultraviolet", "funding_scheme_id": 3264, "funding_scheme": "START-UP 2018", "department": "Exacte en Natuurwetenschappen", "sub_department": "Exacte en Natuurwetenschappen", "start_date": "2019-09-01T00:00:00", "end_date": "2023-08-31T00:00:00", "reporting_year": 2018, "summary_nl": "The central aim in Quantum Gravity is to construct a quantum theory of spacetime geometry that is mathematically consistent, predictive to arbitrarily high energies, and compatible with current understanding of the gravitational force at low energies. Standard perturbation theory, in which one assumes moderate quantum fluctuations around a smooth spacetime background, fails to accomplish this due to the nonrenormalizability of the gravitational interaction. Taking for granted large quantum fluctuations at high energies, i.e. at the tiniest length scales, one has to rethink the concepts of renormalization: how do the quantum laws of spacetime geometry change when probing physics at smaller and smaller length scales? A promising scenario, referred to as asymptotic safety, is that the quantum laws stabilize beyond the Planck scale: the geometry in the deep ultraviolet regime is governed by a nonperturbative fixed point of the renormalization group flow where the laws acquire an exact scaling symmetry. The combination of self-similarity and high curvatures on arbitrarily small scales suggests that spacetime geometry has to acquire fractal properties that are quite different from the smooth spacetime we experience on macroscopic scales. \n\n\n\nThe aim of this project is to construct and study the first explicit examples of quantum geometries in three and four dimensions with such exact scaling symmetries that may serve as the ultraviolet fixed point of asymptotically safe gravity. To this end a recent mathematical construction will be generalized that was previously shown to exhaust all possible ultraviolet fixed points of quantum gravity in two dimensions. It relies on the assembly of higher-dimensional geometries from simpler scale-invariant constituents in ways that have not previously been considered from the perspective of high-energy physics.", "summary_en": "The central aim in Quantum Gravity is to construct a quantum theory of spacetime geometry that is mathematically consistent, predictive to arbitrarily high energies, and compatible with current understanding of the gravitational force at low energies. Standard perturbation theory, in which one assumes moderate quantum fluctuations around a smooth spacetime background, fails to accomplish this due to the nonrenormalizability of the gravitational interaction. Taking for granted large quantum fluctuations at high energies, i.e. at the tiniest length scales, one has to rethink the concepts of renormalization: how do the quantum laws of spacetime geometry change when probing physics at smaller and smaller length scales? A promising scenario, referred to as asymptotic safety, is that the quantum laws stabilize beyond the Planck scale: the geometry in the deep ultraviolet regime is governed by a nonperturbative fixed point of the renormalization group flow where the laws acquire an exact scaling symmetry. The combination of self-similarity and high curvatures on arbitrarily small scales suggests that spacetime geometry has to acquire fractal properties that are quite different from the smooth spacetime we experience on macroscopic scales. \n\n\n\nThe aim of this project is to construct and study the first explicit examples of quantum geometries in three and four dimensions with such exact scaling symmetries that may serve as the ultraviolet fixed point of asymptotically safe gravity. To this end a recent mathematical construction will be generalized that was previously shown to exhaust all possible ultraviolet fixed points of quantum gravity in two dimensions. It relies on the assembly of higher-dimensional geometries from simpler scale-invariant constituents in ways that have not previously been considered from the perspective of high-energy physics.", "award_amount": 423130, "grant_id": "https://doi.org/10.61686/ZRBMV44047", "summary_updates": [ { "submission_date": "2023-11-30T17:07:44", "update_en": "The project has taken important steps towards constructing microscopic models of quantum spacetime. We generalized recent mathematical constructions of two-dimensional toy universes to the three-dimensional setting, giving rise to new random geometries that can be put to test as ultraviolet fixed points of quantum gravity. Our findings were corroborated by putting gravity on the lattice, while advances were made in the mathematics of random geometry.", "update_nl": "Het project heeft belangrijke stappen gezet in de constructie van microscopische modellen van kwantumruimtetijd. We hebben recente wiskundige constructies van twee-dimensionale speelgoeduniversa gegeneraliseerd naar drie dimensies, resulterend in nieuwe stochastische geometrieën die kunnen worden getest als ultraviolette vaste punten van de kwantumzwaartekracht. Onze bevindingen werden bevestigd door de zwaartekracht op een rooster te plaatsen, terwijl vooruitgang is geboekt in de wiskunde van stochastische meetkunde." } ], "project_members": [ { "role": "Researcher", "member_id": 433631, "last_name": "Castro Bermudez", "degree_post_nominal": "BSc", "initials": "B.A.", "first_name": "Alicia", "organisation": "Radboud Universiteit Nijmegen||Faculteit der Natuurwetenschappen, Wiskunde en Informatica", "organisation_id": 49329, "ror": "https://ror.org/016xsfp80", "active": false }, { "role": "Researcher", "member_id": 437929, "last_name": "Lionni", "initials": "J.L.", "first_name": "Luca", "organisation": "Radboud Universiteit Nijmegen||Faculteit der Natuurwetenschappen, Wiskunde en Informatica", "organisation_id": 49329, "ror": "https://ror.org/016xsfp80", "active": false }, { "role": "Main Applicant", "member_id": 374048, "last_name": "Budd", "degree_pre_nominal": "dr.", "initials": "T.G.", "first_name": "Timothy", "organisation": "Radboud Universiteit Nijmegen||Faculteit der Natuurwetenschappen, Wiskunde en Informatica||Institute for Mathematics, Astrophysics and Particle Physics (IMAPP)||High Energy Physics", "organisation_id": 72939, "ror": "https://ror.org/016xsfp80", "active": true }, { "role": "Project leader", "member_id": 374048, "last_name": "Budd", "degree_pre_nominal": "dr.", "initials": "T.G.", "first_name": "Timothy", "organisation": "Radboud Universiteit Nijmegen||Faculteit der Natuurwetenschappen, Wiskunde en Informatica||Institute for Mathematics, Astrophysics and Particle Physics (IMAPP)||High Energy Physics", "organisation_id": 72939, "ror": "https://ror.org/016xsfp80", "active": true } ], "products": [ { "title": "Scale-invariant random geometry from mating of trees: a numerical study", "year": 2023, "edition": "107", "start": 26010, "type": "Wetenschappelijk artikel", "url_open_access": "10.1103/PhysRevD.107.026010", "journal_title": "Physical Review D", "authors": [ { "last_name": "Castro", "initials": "A", "first_name": "Alicia", "role": "Auteur" }, { "last_name": "Budd", "initials": "T", "first_name": "Timothy", "role": "Auteur" } ] }, { "title": "Critical JT gravity", "year": 2023, "edition": "36", "start": 1, "end": 27, "type": "Wetenschappelijk artikel", "url_open_access": "10.1007/JHEP08(2023)036", "journal_title": "Journal of High Energy Physics", "authors": [ { "last_name": "Castro", "initials": "A", "first_name": "Alicia", "role": "Auteur" } ] }, { "title": "The tensor Harish-Chandra–Itzykson–Zuber integral I: Weingarten calculus and a generalization of monotone Hurwitz numbers", "year": 2023, "edition": "1", "start": 1, "end": 43, "type": "Wetenschappelijk artikel", "url_open_access": "https://doi.org/10.4171/jems/1315", "journal_title": "Journal of the European Mathematical Society", "authors": [ { "last_name": "Collins", "initials": "B", "first_name": "Benoît", "role": "Auteur" }, { "last_name": "Lionni", "initials": "L", "first_name": "Luca", "role": "Auteur" }, { "last_name": "Gurau", "initials": "R", "first_name": "Razvan", "role": "Auteur" } ] }, { "title": "The Tensor Harish-Chandra–Itzykson–Zuber Integral II: Detecting Entanglement in Large Quantum Systems", "year": 2023, "edition": "401", "start": 669, "end": 716, "type": "Wetenschappelijk artikel", "url_open_access": "https://doi.org/10.1007/s00220-023-04653-5", "journal_title": "Communications in Mathematical Physics", "authors": [ { "last_name": "Collins", "initials": "B", "first_name": "Benoît", "role": "Auteur" }, { "last_name": "Lionni", "initials": "L", "first_name": "Luca", "role": "Auteur" }, { "last_name": "Gurau", "initials": "R", "first_name": "Razvan", "role": "Auteur" } ] }, { "title": "One-matrix differential reformulation of two-matrix models", "year": 2022, "edition": "8", "start": 2250026, "type": "Wetenschappelijk artikel", "url_open_access": "https://doi.org/10.1142/S0129055X2250026X", "journal_title": "Reviews in Mathematical Physics", "authors": [ { "last_name": "Thürigen", "initials": "J", "first_name": "Johannes", "role": "Auteur" }, { "last_name": "Brunekreef", "initials": "J", "first_name": "Joren", "role": "Auteur" }, { "last_name": "Lionni", "initials": "L", "first_name": "Luca", "role": "Auteur" } ] }, { "title": "Lessons from the Mathematics of Two-Dimensional Euclidean Quantum Gravity", "year": 2023, "edition": "1", "start": 1, "end": 55, "type": "Productbijdrage", "url_open_access": "https://doi.org/10.1007/978-981-19-3079-9_85-1", "city": "Singapore", "publisher": "Springer", "authors": [ { "last_name": "Budd", "initials": "T", "first_name": "Timothy", "role": "Auteur" }, { "last_name": "Bambi", "initials": "C", "role": "Editor" }, { "last_name": "Shapiro", "initials": "I", "role": "Editor" }, { "last_name": "Modesto", "initials": "L", "role": "Editor" } ] }, { "title": "Simple peeling of planar maps with application to site percolation", "year": 2021, "start": 1, "end": 35, "type": "Wetenschappelijk artikel", "url_open_access": "10.4153/S0008414X21000146", "journal_title": "Canadian Journal of Mathematics", "authors": [ { "last_name": "Budd", "initials": "T", "first_name": "Timothy", "role": "Auteur" }, { "last_name": "Curien", "initials": "N", "role": "Auteur" } ] }, { "title": "On polynomials counting essentially irreducible maps", "year": 2022, "edition": "29", "start": 245, "type": "Wetenschappelijk artikel", "url_open_access": "10.37236/9746", "journal_title": "Electronic Journal of Combinatorics", "authors": [ { "last_name": "Budd", "initials": "T", "first_name": "Timothy", "role": "Auteur" } ] }, { "title": "Irreducible Metric Maps and Weil–Petersson Volumes", "year": 2022, "start": 1, "end": 31, "type": "Wetenschappelijk artikel", "url_open_access": "10.1007/s00220-022-04418-6", "journal_title": "Communications in Mathematical Physics", "authors": [ { "last_name": "Budd", "initials": "T", "first_name": "Timothy", "role": "Auteur" } ] } ] } ] }