Home Page of N.P. (Klaas) Landsman

Professor of Mathematical Physics, Department of Mathematics, Institute for Mathematics, Astrophysics, and Particle Physics (IMAPP), Radboud University Nijmegen

Co-founder of NWO-Cluster Fellowship of Geometry and Quantum Theory (GQT), Dutch Institute for Emergent Phenomena (DIEP), and Radboud Center for Natural Philosophy

Spinoza Prize Interview Voxweb Interview Radboud Recharge Interview De Gelderlander Interview Nederlands Tijdschrift voor Natuurkunde


Foundations of General Relativity: From Einstein to Black Holes (Radboud University Press, Open Access)
First printing (October 2021) Second corrected and expanded printing (July 2022)

Naar alle ONwaarschijnlijkheid (Prometheus, 2018)

Foundations of Quantum Theory: From Classical Concepts to Operator Algebras (Springer, 2017, Open Access)

The Challenge of Chance (Springer, 2016, Open Access)

Requiem voor Newton (Contact, 2005)

Mathematical Topics Between Classical and Quantum Mechanics (Springer, 1998)

Scientific papers

Lecture Notes

Popular papers/Opinions


Book reviews (outdated)

Recent and upcoming talks (outdated)

Curriculum Vitae

List of Publications

Teaching Record


IMAPP, Faculty of Science
Radboud University Nijmegen
Heyendaalseweg 135
6525 AJ Nijmegen

email: landsman at math.ru.nl

Research Area: Mathematical Principles of Natural Philosophy

* Randomness, determinism, and emergence
* Foundations of quantum theory
* History and philosophy of black hole theory (notably Penrose and Hawking)
* History and philosophy of mathematics (notably Wittgenstein)
* Foundations of thermodynamics and statistical mechanics
* Measurement problem, spontaneous symmetry breaking (dormant)
* Topos theory and quantum logic (dormant)
* Noncommutative geometry and (strict) deformation quantization (dormant)
* Quantum fied theory at finite temperature (dormant)

Editorial Board member of:

Foundations of Physics

Studies in History and Philosophy of Modern Physics

Fundamental Theorie of Physics

Mathematical Physics Studies

International Journal of Geometric Methods in Modern Physics


Le hasard ne favorise que les esprits prepares (Louis Pasteur)

Der Philosoph ist nicht Buerger einer Denkgemeinde. Das ist, was ihn zum Philosophen macht
(Ludwig Wittgenstein)

The secret to life is to have a task, something you devote your entire life to, something you bring everything to , every minute of the day for your whole life. And the most important thing is - it must be something you cannot possibly do
(Henry Moore)

Darahku merah tak sudi dijajah!

Ik en jij zijn samen wij (Felix Landsman)

Ik had nooit opgekeken tegen hoog, ook nooit neergekeken op laag (Johan Cruijff)

Ik kom uit Friesland. Ik loop niet voor andere meesters (Chris Zaal)

Door veel te begrijpen, heb ik niets af kunnen maken (the last words of Hugo de Groot)

Als componist schrijf je iets, je ziet wat je fout hebt gedaan en dat probeer je beter te doen. Dat proces gaat door tot je zeventigste, tachtigste
(Louis Andriessen)

Succes is niet een kwestie van een grote stap, maar van heel veel kleine stapjes. Je moet niet denken: ik wil vijftig winkels neerzetten. Je moet eerst die ene winkel goed doen. Je moet die ene bh goed kunnen maken (Marlies Dekkers)

I do not like this top ten business. It is the bottom ten that I like. You have got to go for the little things, the stones that make up the wall. Science is a tremendous collaboration of people from all over the world adding little bricks to a massive wall. The individual bricks are what make it work, and not the milestones (Donald Knuth)

Support of basic research in the universities and research institutes must leave the internal control of policy, personnel, and the method and scope of the research to the institutions themselves. This is of the utmost importance. (Vannevar Bush)

Dann giesst die Wissenschaft oft ihren wohltaetigen Segen auf das Leben aus, wenn sie dasselbe gewissermassen zu vergessen scheint (Wilhelm von Humboldt)

There is only one race: the human race (heard from black perfomer at Venice Beach)

The vulgarity of the present disgusted him. Kafu could only love in retrospect, and celebrate what has disappeared (Ian Buruma, A Tokyo Romance, p. 55, about the Japanese writer Nagai Kafu)

If everything is under control, you're not going fast enough (Mario Andretti)

PhD students:

Mark A. Robson (Cambridge, 1995): The Geometric Quantization of Constrained Systems

Urs A. Wiedemann (Cambridge, 1994): Constraints and Symmetry Breaking in Quantum Field Theory

Ken K. Wren (Cambridge, 1998): Constrained Quantization of Yang-Mills Theory via Rieffel Induction

Hessel Posthuma (Amsterdam, 2003): Quantization of Hamiltonian loop group actions

Rogier Bos (Nijmegen, 2007): Groupoids in geometric quantization

Peter Hochs (Nijmegen, 2008): Quantisation commutes with reduction for cocompact Hamiltonian group actions (co-supervisor: Gert Heckman)

Niels Kowalzig (Utrecht, 2009): Hopf algebroids and their cyclic theory (co-supervisors: Marius Crainic, Ieke Moerdijk, Hessel Posthuma)

Chris Heunen (Nijmegen, 2009): Categorical quantum models and logics (co-supervisor: Bart Jacobs)

Pieter Naaijkens (Nijmegen, 2012): Anyons in infinite quantum systems (supervisor: Michael Mueger)

Sander Wolters (Nijmegen, 2013): Quantum Toposophy

Jord Boeijink (Nijmegen, 2014): Dirac operators, gauge systems and quantisation? (supervisor: Walter van Suijlekom)

Roberta Iseppi (Nijmegen, 2015): The BV Formalism for Matrix Models: A Noncommutative Geometry Approach (supervisor: Walter van Suijlekom)

Bert Lindenhovius (Nijmegen, 2016) C(A)

Sohail Sheikh (Nijmegen, 2019) Group-crossed extensions of representation categories in algebraic quantum field theory (supervisor: Michael Mueger)

Leo Garcia Heveling (Nijmegen, 2023) Causality and Time in Non-smooth Lorentzian Geometry (supervisor: Annegret Burtscher)

MSc students:

Edwin Koopman (Amsterdam, 1989): Dimensional reduction at high temperature revisited

Joris Portegies Zwart (Amsterdam, 1998): BRST reduction and quantization of constrained Hamiltonian systems

Erik van Erp (Amsterdam, 2000): The Atiyah-Singer index theorem, K-theory, and quantization

Rachel Brouwer (Amsterdam, 2001): A bicategorical approach to Morita equivalence for rings and von Neumann algebras

Walter van Suijlekom (Amsterdam, 2002): The noncommutative Lorentzian cylinder as an isospectral deformation

Fonger Ypma Amsterdam, 2004): Quasicrystals, C*-algebras and K-theory

Bram Buijs Amsterdam, 2005): The cohomological descent method [ps] [pdf]

Bram Mesland (Amsterdam, 2005): Algebraic K-theory, periodic cyclic homology, and the Connes-Moscovici index theorem [ps] [pdf]

Michelangelo Vargas Rivera (Amsterdam, 2005): Noncommutative geometry and the integer quantum Hall effect [pdf]

Martijn Caspers (Nijmegen, 2008, winner of GQT Thesis Prize): Gelfand spectra of C*-algebras in topos theory

Hanneke Janssen (+) (Nijmegen, 2008, winner of Jim Cushing Memorial Prize): Reconstructing Reality (co-supervisor: Jos Uffink)

Ronnie Hermens (Nijmegen, 2009, winner of Hanneke Janssen Memorial Prize): Quantum mechanics: from realism to intuitionism

Richard Sanders (Nijmegen, 2012): Commutative spectral triples and the spectral reconstruction theorem

Sander Uijlen (Nijmegen, 2013): Categorical aspects of von Neumann algebras and AW*-algebras

Ruben Stienstra (Nijmegen, 2014): Complete motion in classical and quantum mechanics (winner of ASML Afstudeerprijs of the KHMW, GQT scriptieprijs 2015 and RU afstudeerprijs 2015)

Christian Budde (Nijmegen, 2015): Operator algebras and unbounded self-adjoint operators

Marco Stevens (Nijmegen, 2015): The Kadison-Singer Property

Daan van der Maas (Nijmegen, 2016): Classification of Hamiltonians under Symmetry Constraints

Davide DeMelo (Nijmegen, 2017): Compatibilism and actual miracles

Teun van Nuland (Nijmegen, 2017): Quantization and the resolvent algebra

Chris van de Ven (Nijmegen, 2018): Properties of quantum spin systems and their classical limit

Baukje Debets (Nijmegen, 2018): Properties of graph C*-algebras in the Cuntz-Krieger, Cuntz-Pimsner, and groupoid models (supervisor: Francisca Arici)

Jan Glowacki (Nijmegen, 2019): Groupoid symmetry and constraint bracket of General Relativity Revisited

Daan Janssen (Nijmegen, 2019): Quantum fields on non-globally hyperbolic space-times and the information loss paradox

Kitty Rang (Nijmegen, 2019): Symmetries in algebraic quantum theory

Nesta van der Schaaf (Nijmegen, 2020): Diffeology, groupoids, and Morita Equivalence

Thomas Manschot (Nijmegen, 2020):Semiclassical analysis: The double well potential in the semiclassical limit

Christo Morison (Amsterdam, 2020):Uniformisation as a Bridge Between Ricci Flow and General Relativity in Two Spatial Dimensions

Matijs Sonnemans (Nijmegen, 2020): The demon and the abacus: An analysis, critique, and reappreciation of digital physics (co-supervisor: Frederik Bakker)

Jonas Kamminga (Nijmegen, 2021): Strengths and limitations of quantum entanglement (supervisor: Ronald de Wolf)

Berend Schneider (Nijmegen, 2023): Reading the Cosmic Palm: Spinors, the Weyl Tensor Fingerprint, and Mass in General Relativity (co-supervisor: Beatrice Bonga)

Sepehr Hassannejad Nazir (Nijmegen, 2023): Indeterminism in General Relativity

Thomas Vissers (Nijmegen, 2023): A Comprehensive Evaluation of the Viability of Superdeterminism (co-supervisor: Henk de Regt)

BSc students:

Behnam Norouzizadeh (Utrecht, 2004): Coarse Geometry and K-Homology

Mirte Dekkers (Nijmegen, 2006): De Dutch Book Stelling

Bram Wouters (Nijmegen, 2008): Determinisme onder de kwantummechanica

Tim de Laat (Nijmegen, 2008): Synthetic differential geometry: an application to Einstein's equivalence principle

Matthias den Hartog (Nijmegen, 2008): Muziek en wiskunde

Marianne Coenen & Tom Huls (Nijmegen, 2008): Modelselectie: AIC en BIC

Anna Kiriliouk, Kris Schoorl, Tjapko Struik, Tim Verheijen (Nijmegen, 2009): Zevenheuvelenloop Excel sheet

Corine Baayen, Margo Ermens, Gerjan Hebbink, Sara Houweling, Marleen Kock (Nijmegen, 2010): Wiskundig onderzoek en de maatschappij: een case study (gebaseerd op de wiskundige ontwikkelingen achter het NS-Spoorboekje)

Frank Buijnsters, Tim van Lent, Wouter van Orsouw (Nijmegen, 2010): Het LLL-algoritme: een case-study naar wiskunde en technologische innovatie

Michael Agathos, Master Class Test Problem (Utrecht, 2010): The fundamental interactions in noncommutative geometry

Maciej Koch-Janusz, Master Class Test Problem (Utrecht, 2010): Twisted index theorems and the fractional Quantum Hall Effect

Wilke Castelijns, Maria van Rooijen, Patrick Uiterwijk, David Venhoek (Radboud Honours Program 3d year Thesis, 2012): Quantum cryptography: between science and businsess Cover

Robin Reuvers, BSc Thesis (Nijmegen, 2012): A Flea on Schroedinger's Cat including movies

Jan-Willem Goossens (Nijmegen, 2013): Kwantum Balletje Balletje

Dennis Hendrikx (Nijmegen, 2013): Do Hidden Variables Improve Quantum Mechanics?

Daan van der Maas (Nijmegen, 2013): Indistinguishabe Particles in Quantum Theory

Victor Hissink Muller (Nijmegen, 2015): Symmetrie in de kwantummechanica: Stellingen van Wigner, Kadison, en Jacobson-Rickart-Kadison

Jeroen Slot (Nijmegen, 2017): Compact perturbations of operators on Hilbert spaces

Laura van Schijndel (Nijmegen, 2017): Stone and Heyting duality for classical and intuitionistic propositional logic

Nesta van der Schaaf (Nijmegen, 2017): Classical and quantum particles in Galilean and Poincare spacetimes

Yari Kraak (Nijmegen, 2018): On compatibility properties of quantum observables represented by positive-operator valued measures

Loek van Rossem (Nijmegen, 2018): Gravity and the flea: A gravitational approach to the measurement problem

Eva-Maria Hekkelman (Nijmegen, 2018): Properties of the lattice O(Sigma_A) concerning intuitionistic quantum logic

Quinten Rutgers (Nijmegen, 2018): Intuitionistic quantum logic

Myrthe Scheepers (Nijmegen, 2018): Why the quantum? Bananaworld

Sven Etienne (Nijmegen, 2019): Bell's Theorem

Jonas Kamminga (Nijmegen, 2019): An algorithmic perspective on randomness in quantum mechanics (co-supervisor: S.A. Terwijn)

Ian Koot (Nijmegen, 2019): The Frauchiger-Renner paradox

Tein van der Lugt (Nijmegen, 2020): Indeterministic finite-precision physics and intuitionistic mathematics

Sven Schakenbos (Nijmegen, 2020): The limits of applying temporal logic to the problem of time

Febe Verstraten (Nijmegen, 2021): Is het menselijk bewustzijn een machine? Wat impliceren de onvolledigheidsstellingen van Goedel?

Tjitske Koster (Nijmegen, 2021): (John)Stone duality (co-supervisor: Magdalena Kedziorek)

Tom Hegeman (Nijmegen, 2023): Analysis of the Works by Simon Stevin (co-supervisor: Riccardo Cristoferi)

Kirti Singh (Nijmegen, 2023): Is Wiskunde een Spel?