Postdoc Positions: Origins of Irreversibility

Employment 1.0 FTE Gross monthly salary € 3,706 - € 5,760 Required background PhD Organizational unit Faculty of Science Application deadline 14 October 2026 Join an ambitious interdisciplinary research project exploring some of the most profound questions in modern science. As part of the Origins of Irreversibility team at the Radboud Center for Natural Philosophy, you will work alongside physicists, mathematicians, historians and philosophers to investigate the origins of entropy, randomness, chaos and irreversible behaviour in nature.

We are looking for three postdoctoral researchers to join the interdisciplinary Origins of Irreversibility project: one in mathematical physics, one in theoretical physics and one in the history of physics. Together, you will investigate one of the deepest problems in fundamental science: how irreversible macroscopic behaviour can arise from microscopic laws that are typically reversible. The project connects statistical mechanics, quantum theory and gravitational physics with historical and conceptual research on entropy, randomness and chaos.

What makes these positions distinctive is the opportunity to pursue specialised research while being part of a genuinely interdisciplinary team. We particularly welcome researchers who are interested in crossing disciplinary boundaries: physicists and mathematicians who enjoy conceptual and foundational questions, as well as historians of physics who are interested in engaging seriously with the content of the science they study.

You will be an active member of RCNP. You will collaborate with the other postdoctoral researchers, PhD candidates and senior investigators, participate in seminars and reading groups, contribute to workshops and conferences, and help build connections between mathematical physics, theoretical physics, history and philosophy of physics. There is considerable freedom to shape the precise research direction according to your expertise and interests, provided that it contributes to the overarching questions of the project.

The Mathematical physics position will contribute to the mathematical foundations of entropy, randomness and irreversibility, with possible directions including large deviation theory, algorithmic randomness, ergodic theory, quantum entropy, operator algebras and their applications to statistical physics and/or black hole thermodynamics.

The Theoretical physics position will focus on gravitational and holographic systems out of equilibrium, with possible topics including dynamical and cosmological horizons, gravitational entropy, Noether charge methods, holographic coarse-graining, chaos, black hole heat engines and quantum field theory in curved space-time. These two parts of the project are designed to interact closely: mathematical tools concerning entropy, randomness and operator algebras feed into the gravitational research, while problems arising in gravity and holography motivate new mathematical questions.

The History of physics position will investigate the history of chaos, randomness and irreversibility, from nineteenth-century statistical physics to the rise of chaos theory as an interdisciplinary movement in the late twentieth century. Possible themes include the relationship between Maxwell's and Boltzmann's ideas of molecular chaos and later mathematical notions of chaos; the circulation of concepts such as randomness, entropy and unpredictability between physics, mathematics, meteorology and other disciplines; the prominence of chaos theory in the 1970s and 1980s; and its longer-term methodological and conceptual impact. The historical research is intended not simply as a parallel study, but as a source of conceptual insight for the contemporary physics and mathematics in the project.

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Does this sound like you?

• You hold, or will have obtained before the starting date, a PhD in a field relevant to one of the three positions, such as mathematical physics, mathematics, theoretical physics, history of science or history of physics.
• You have a strong research record appropriate to your career stage and the position for which you are applying.
• You are able to conduct independent research and are enthusiastic about developing new research directions in collaboration with others.
• You have a demonstrable interest in fundamental questions concerning entropy, irreversibility, randomness, chaos, emergence or closely related topics.
• You are interested in interdisciplinary collaboration and willing to engage seriously with fields outside your own primary discipline.
• You are communicative, curious, critical, loyal to colleagues and proactive.
• You possess excellent written and oral English communication skills.
• You are willing to participate actively in the intellectual life of the Radboud Center for Natural Philosophy, including its seminars, reading groups, workshops and visitor programme. What we offer you

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• We will give you a temporary employment contract of 2 year(s).
• Your salary within salary scale 10 depends on your previous education and number of years of (relevant) work experience. The amounts in the scale are based on a 38-hour working week.
• You will receive an 8% holiday allowance and an 8,3% end-of-year bonus.
• You will receive extra days off. With full-time employment, you can choose between 30 or 41 days of annual leave instead of the statutory 20. Additional employment conditions

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Work and science require good employment practices. Radboud University's primary and secondary employment conditions reflect this. You can make arrangements for the best possible work-life balance with flexible working hours, various leave arrangements and working from home. You are also able to compose part of your employment conditions yourself. For example, exchange income for extra leave days and receive a reimbursement for your sports membership. In addition, you receive a 34% discount on the sports and cultural activities at Radboud University as an employee. And, of course, we offer a good pension plan. We also give you plenty of room and responsibility to develop your talents and realise your ambitions. Therefore, we provide various training and development schemes.

Where you will be working

The Radboud Center for Natural Philosophy (RCNP) is a research centre at Radboud University where mathematicians, physicists, historians and philosophers work together on foundational questions in the natural sciences. Its research focuses especially on determinism, randomness and emergence in modern physics. The centre brings together researchers from mathematical and theoretical physics and from the history and philosophy of science, and organises seminars, reading groups, workshops, conferences and an international visitor programme.

The three postdoctoral researchers will join the Origins of Irreversibilityproject funded by the John Templeton Foundation, which brings together Klaas Landsman, Manus Visser, Marij van Strien, Kian Salimkhani and other researchers at RCNP, alongside new postdoctoral researchers and PhD candidates. Within the project, mathematical physics provides tools for understanding entropy and randomness, theoretical physics studies their role in gravitational and holographic systems, and historical and philosophical research critically examines the concepts on which these investigations rely. Close interaction between these areas is a central part of the project.

The physics and mathematics postdoctoral researchers will also be employed by the Institute for Mathematics, Astrophysics and Particle Physics (IMAPP), in particular the mathematics department, and will benefit from the existing expertise in mathematical physics, high-energy theory, classical and quantum gravity, and black hole physics. RCNP and IMAPP offer an international and collaborative research environment with regular seminars and informal scientific interaction. Further, the historical postdoctoral researcher will be part of theCenter for the History of Philosophy and Science (CHPS) within the Faculty of Philosophy, Theology and Religious Studies (FFTR). CHPS brings historians of philosophy and historians of science together and has particular expertise in the historical development of the natural sciences, the relations between philosophy and science, and the epistemological, methodological and ontological foundations of the sciences.

Faculty of Science

The Faculty of Science (FNWI), part of Radboud University, engages in groundbreaking research and excellent education. In doing so, we push the boundaries of scientific knowledge and pass that knowledge on to the next generation.

We seek solutions to major societal challenges, such as cybercrime and climate change and work on major scientific challenges, such as those in the quantum world. At the same time, we prepare our students for careers both within and outside the scientific field.

Currently, more than 1,300 colleagues contribute to research and education, some as researchers and lecturers, others as technical and administrative support officers. The faculty has a strong international character with staff from more than 70 countries. Together, we work in an informal, accessible and welcoming environment, with attention and space for personal and professional development for all.

Radboud University

At Radboud University, we aim to make an impact through our work. We achieve this by conducting groundbreaking research, providing high-quality education, offering excellent support, and fostering collaborations within and outside the university. In doing so, we contribute indispensably to a healthy, free world with equal opportunities for all. To accomplish this, we need even more colleagues who, based on their expertise, are willing to search for answers. We advocate for an inclusive community and welcome employees with diverse backgrounds, cultures, and perspectives.

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Is this the job for you?

Address your letter of application to Manus Visser. We look forward to receiving your application. It is possible to apply for more than one position. In the online application form, you can specify the position(s) for which you wish to be considered. Please fill in the application form and attach the following:

• Your motivation letter, in which you describe your academic background, motivation for applying, and potential research interests.
• Your CV, including a list of publications.
• The names and contact details of three references.
• The position(s) you would like to apply for.

The first interviews will take place on Tuesday 27 October. You will preferably start your employment on 1 January 2027, or later upon further agreement, but no later than 1 September 2027. We can imagine you're curious about our application procedure. It describes what you can expect during the application procedure and how we handle your personal data and internal and external candidates. Do you already work at Radboud University and have questions about making an internal move? Learn more about internal applications. Application deadline 14 October 2026