About the OKC

The Oskar Klein Centre (OKC) brings together scientists from the departments of physics and astronomy at Stockholm University and the department of physics at the Royal Institute of Technology (KTH). It was created thanks to a 10-year Linnaeus grant from the Swedish Research Council in 2008.

Today, the OKC is a rich scientific environment that comprises more than one hundred particle physicists, astronomers, astrophysicists, and cosmologists.

The OKC recently founded the excellence centre EDUCATE thanks to a generous grant from the Swedish Research Council (Vetenskapsrådet).

Organization

All researchers at the Oskar Klein Centre are appointed in one of the participating departments. The OKC itself breaks down those departmental boundaries, and instead fosters collaborations between different areas of research. The Centre has a bottom up organization: OKC-researchers conceive of and organize activities that contribute to the overall research questions driving the OKC.

Overview of the organizational structure of the Oskar Klein Centre.Zoom image

Organizational structure of the Oskar Klein Centre.

The daily running of OKC is overseen by the OKC director, in close collaboration with the Steering Group. The directors and steering group are appointed for 3-year terms. The steering group is composed of:

  • The OKC Director
  • 3 representatives from Cosmology, Particle Astrophysics, and Strings (CoPS) at SU Fysikum
  • 3 representatives from Elementary Particle Physics (ELPA) at SU Fysikum
  • 3 representatives from SU Astronomy
  • 3 representative from Particle and Astroparticle Physics at KTH Physics

The Steering Group

The long-term strategy for the Oskar Klein Centre is overseen by the Scientific Advisory Board.

The Scientific Advisory Board

Steering Group Minutes (authorized access only)

Some of the regular activities are listed here—our full calendar is available on our Indico page.

  • Working Group meetings: The OKC has six Working Groups, centered around a particular research topic. They are: Beyond the Standard Model, Cosmology & Extragalactic Astrophysics, Extreme Objects, Machine Learning, Theoretical Cosmology and Theory.
  • Journal Club meetings: Aside from the official Working Groups, OKC researchers organize a number of journal clubs on topics of common interest. These include galaxy formation and evolution, machine learning, axions, or kilonovae. Any OKC-researcher is free to start their own journal club.
  • OKC Colloquia and fika: Every tuesday afternoon, everyone at the OKC is invited to the OKC Colloquium. The colloquia cover topics that are of broad interest to all researchers at OKC. They are followed by a fika.
  • Scientific fikas: On friday afternoon, students, PhD students and Postdocs get together for informal “scientific fikas”. These are informal talks on a topic of the speaker’s choice. The fikas provide an opportunity for early-career researchers to practice public speaking in a low-stakes environment and to network with their peers.
  • OKC day: The OKC day is a regular, once-per-year day-long workshop for all researchers at OKC. The day is filled with scientific discussions and professional development workshops. It’s a unique chance for everyone at OKC to get together and delve deeper into where the OKC should go next.

The Oskar Klein Centre organizes and participates in many events open to the general public. At the OKC, we love to talk to people about what we are interested in, the problems we are trying to solve, and the sciencific questions we search to understand.

Past outreach activities

OKC in the media

Logo and templates

Subscribe to our Newsletter for weekly updates on events, Working Group and Journal Club meetings; as well as our latest publications, AI news and more.

Research at the Oskar Klein Centre

Research at the Oskar Klein Centre is broadly centered around questions in cosmology, astrophysics, and cosmoparticle physics. These include:

  • What is the nature of dark matter and dark energy?
  • What is the structure and fate of our Universe?
  • How do galaxies form and evolve?
  • How do extreme objects like supernovae, neutron stars and black holes behave?
  • What is the correct theory of gravity?
  • ... and more.

OKC researchers publish their work in leading research journals.

List of recent publications involving OKC-researchers

Research at the OKC is primarily organized in Working Groups. The Working Groups are defined by common research topic—not by disciplinary boundaries. Scientists can decide independently to contribute to one or more working groups according to their field of research or simply because they want to learn more about a specific subject. Each Working Group receives its own research budget. Members of the Working Groups decide how to organize the meetings and what projects to pursue. There are regular joint meetings between different working groups, to foster further collaboration.

All Working Group meetings are listed on the Oskar Klein Centre's Indico Server.

Beyond the Standard Model Working Group

Cosmology and Gravity Working Group

Extreme Objects Working Group

Machine Learning Working Group

Theoretical Cosmology Working Group

Theory Working Group

About Oskar Klein

Early career

Oskar Klein (1894-1977) was 23 years old when he traveled to Copenhagen to work with Niels Bohr. After various temporary positions, he became professor in theoretical physics at Stockholm University (then "Stockholm Högskola") in 1931. He stayed there until his retirement in 1962. Klein had a broad interest in various fields of physics. He is perhaps best known for the Klein-Gordon equation and the Klein-Nishina equation. His attempts to unify general relativity and electromagnetism by introducing a five-dimensional spacetime date back to 1926. They are today known as Kaluza-Klein theory.

Extended biography of Oskar Klein

Oskar Klein

Since 1988, the Oskar Klein Centre organizes the yearly Oskar Klein Memorial Lecture. The Oskar Klein Memorial Lectures are sponsored by The Royal Swedish Academy of Sciences through its Nobel Committee for Physics and by Stockholm University.

List of previous memorial lectures

The 2025 Oskar Klein Memorial Lecture will be given by Reinhard Werner on Thursday 09 October at 15:15. Location TBA.

The lecture is sponsored by the Royal Swedish Academy of Sciences through its Nobel Institute for Physics, and by Stockholm University.

Title: 100 years of quantum mechanics and quantum information

Abstract: An important principle for Heisenberg's early work was to build a theory on observable quantities alone. The talk will follow this theme from those early days, to the development of appropriate tools for describing quantum operations, on to their role in modern quantum information theory. 

In his "Uncertainty" paper from 1927 Heisenberg used operational definitions in analogy to Einstein's analysis of simultaneity, in an attempt to ground quantum mechanics in directly observable concepts. Bohr initially had some objections, but with the help of Oskar Klein these differences were resolved and Heisenberg's semiclassical dual wave-particle approach became Copenhagen philosophy. Unfortunately, this did not really work as a basis of the new quantum mechanics, as Einstein tried to point out in his famous debates with Bohr.  Apart from back-of-the-envelope heuristics nothing remained of this approach. 

Meanwhile, operational philosophy became part of the mainstream, and operational formulations of quantum mechanics, more systematic and hence more radical than Heisenberg's, were provided by von Neumann (1927), and then axiomatically by Ludwig around 1970. The mathematics of quantum operations, i.e., completely positive maps, was introduced by Kraus, Davies, Lindblad and others. 

These ideas became fundamental for the rise of quantum information theory. We are accustomed to analyze complex information systems into building blocks, each of which has a description as a completely positive map in the formalism, but also as an instruction set for agents like Alice and Bob. A tacit key assumption for that is that the description of each building block makes sense independently of the other parts. For example, in the resource approach to quantum information typically one agent's operation is to be optimized given the others. One might call this assumption "modular causality", and it is apparently the strongest form of causality that Nature lets us get away with.   

Cosmology and Astroparticle Student and Postdoc Exchange Network (CASPEN)

The CASPEN Program aims to foster scientific advances on topics of mutual interest by enhancing the exchange of ideas and opportunities for collaboration.

General information about the Caspen program from Durham University:

Cosmology and Astroparticle Student and Postdoc Exchange Network

The following institutions participate:

The Oskar Klein Centre (Stockholm University & KTH Royal Institute of Technology, Stockholm, Sweden)

Cosmoparticle Initiative (University College London, United Kingdom)

Center for Cosmology and AstroParticle Physics (Ohio State University, Columbus, Ohio, USA)

Center for Computational Astrophysics, Flatiron Institute (New York City, New York, USA)

Kavli Institute for Particle Astrophysics and Cosmology (Stanford, California, USA)

Institute for Computational Cosmology (Durham University, Durham, United Kingdom)

The primary aim of this scheme is to promote collaboration and to provide scientific and professional development opportunities for students and postdocs. Scientific themes of CASPEN include precision cosmology from large scale structure and the cosmic microwave background, the particle physics and astrophysics of dark matter and neutrinos, high energy cosmic ray and gamma ray physics, and theoretical and observational studies of galaxy formation.

All students and postdocs working in a relevant field are encouraged to apply.

Overview of past visits

    There are no set deadlines as this is a rolling program. You can apply as soon as you know your travel dates. Allocation of funds will be made by the relevant budget holder at the host institution, and is expected to be straight-forward and rapid in well-justified cases. The work can be based on an existing program or a new idea.

    To apply, first identify a potential collaborator from a host institution and agree on a work plan and dates for the visit. Applicants are expected to identify a concrete proposal for a period between 3 days and approximately 2 weeks.

    Apply

    Job opportunities at the OKC

    Are you interested in working at the OKC? PhD and postdoc positions are part of the university educational jurisdiction and are hence granted and administrated by the university institutions. Positions are usually affiliated with a particular project and supervisor. They are listed on the respective university job pages:

    PhD positions at Stockholm University

    PhD positions at KTH

    Postdoc positions at Stockholm University

    Postdoc positions at KTH

    If you are interested in applying for research funding, the following web pages can be helpful to find opportunities and guidance:

    Stockholm University's Office for Research, Engagement and Innovation Services

    KTH's Research Support Office

    Alumni of the Oskar Klein Centre tend to be very successful at securing research grants or other prestigious postdoc positions. Many of our alumni also pursue non-academic careers, with great success.

    Communications Officer

    Samuel Avraham

    samuel.avraham@fysik.su.se

    Last updated: 2025-12-19

    Source: Oskar Klein Centre

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