Postdoctoral Fellow in Physics (Stockholm University)

Institution: Nordita, The Nordic Institute for Theoretical Physics Location: Stockholm, Sweden Posted: 19 Dec 2025 Application Deadline: 20 Jan 2026 Reference Number: SU FV-4638-25 Employment Type: Temporary, Full-time (100%) Contract Duration: Minimum 2 years, maximum 3 years (possible extension under special circumstances) Salary: Individual salary setting Number of Positions: 2 About Nordita Nordita was founded in Copenhagen, Denmark, in 1957 and moved to the AlbaNova University Center in Stockholm, Sweden, in 2007, where it is jointly hosted by KTH Royal Institute of Technology and Stockholm University. Research at Nordita covers a broad range of theoretical physics including astrophysics, biophysics, condensed matter physics, gravitation, cosmology and astroparticle physics, high-energy physics, quantum information, soft matter, and statistical physics/complex systems. The research activity of the local academic staff is supplemented by Nordita Scientific Programs, which bring together groups of leading experts to work on specific topics for extended periods. There is also ample opportunity for collaboration with faculty and research staff at local universities. Further information about Nordita can be found at www.nordita.org. Project Description The candidate will work on the end-to-end modeling of magnetic field evolution from the early Universe to the present epoch. One postdoc will focus on early Universe dynamics, and the other on the dynamics during the recombination era. This is part of a joint effort within the ERC Synergy Grant COSMOMAG with Andrii Neronov (APC and Lausanne), Chiara Caprini (CERN and CNRS), and Franco Vazza (U Bologna). Additional postdoc and PhD positions will be advertised in the following years. Frequent visits between the nodes of COSMOMAG are expected for discussions and joint coordination. The COSMOMAG project aims to pin down the origin of cosmological magnetic fields by developing a unified framework tackling the problem from the initial conditions in the early universe up to present-day observations. The project will study magnetic field generation in the early universe, evolve them numerically, and predict observable signatures today, to be tested via gamma-ray, radio, and gravitational wave observations. The project consists of understanding the evolution of primordial magnetic fields before recombination. The phenomenology of magnetic field decay is still debated, and numerical simulations are essential to establish correct decay laws. We will mainly use the Pencil Code to simulate magnetic field evolution from generation to recombination, complemented by analytical understanding to interpret results. Key topics include: Generation of magnetic fields in the early universe at the end of inflation and during electroweak and QCD phase transitions Magnetic field evolution through the epoch of recombination The successful candidate will work with Professor Axel Brandenburg at Nordita, with close collaborations possible with Professors Chiara Caprini, Andrii Neronov, and Franco Vazza. Regular virtual and in-person meetings with other synergy project members and the astrophysics group at Nordita are expected. Main Responsibilities Conduct research aligned with the project description under the guidance of the PI. Qualification Requirements Hold a Swedish doctoral degree or an equivalent relevant degree from another country. The degree must be completed no later than the employment decision. Assessment Criteria: Advantageous if the doctoral degree was completed no more than three years before the application deadline. Older degrees may also be considered under special circumstances (e.g., sick leave, parental leave, trade union service, clinical attachment, or relevant assignments). Strong research background and familiarity with numerical simulations are highly valued. About the Employment Full-time position for 2–3 years with potential for extension under special circumstances. Start date by agreement: Spring or Fall 2026. Benefits Dynamic interaction between higher education and research in an international environment. Located in Stockholm’s National City Park with good transport links. Stockholm University is committed to equal opportunity and a discrimination-free workplace. Contact Head of Administration: Elizabeth Yang, +46 8 553 784 73, elizabeth.yang@su.se Recruiting Professor: Axel Brandenburg, brandenb@nordita.org Application Instructions Apply via Stockholm University's recruitment system. Attach: Personal letter CV with work experience and publication list Research proposal Contact details for two referees Ensure the application is complete per the instructions in the job advertisement. Instructions for applicants: How to Apply Union Representatives: ST/OFR: st@st.su.se Saco-S: saco@saco.su.se Seko: sekodirekt@seko.se If you apply for this position please say you saw it on Physicaloxy

Institution: Nordita, The Nordic Institute for Theoretical Physics

Location: Stockholm, Sweden

Posted: 19 Dec 2025
Application Deadline: 20 Jan 2026
Reference Number: SU FV-4638-25
Employment Type: Temporary, Full-time (100%)
Contract Duration: Minimum 2 years, maximum 3 years (possible extension under special circumstances)
Salary: Individual salary setting
Number of Positions: 2

About Nordita

Nordita was founded in Copenhagen, Denmark, in 1957 and moved to the AlbaNova University Center in Stockholm, Sweden, in 2007, where it is jointly hosted by KTH Royal Institute of Technology and Stockholm University. Research at Nordita covers a broad range of theoretical physics including astrophysics, biophysics, condensed matter physics, gravitation, cosmology and astroparticle physics, high-energy physics, quantum information, soft matter, and statistical physics/complex systems.

The research activity of the local academic staff is supplemented by Nordita Scientific Programs, which bring together groups of leading experts to work on specific topics for extended periods. There is also ample opportunity for collaboration with faculty and research staff at local universities.

Further information about Nordita can be found at www.nordita.org.

Project Description

The candidate will work on the end-to-end modeling of magnetic field evolution from the early Universe to the present epoch. One postdoc will focus on early Universe dynamics, and the other on the dynamics during the recombination era. This is part of a joint effort within the ERC Synergy Grant COSMOMAG with Andrii Neronov (APC and Lausanne), Chiara Caprini (CERN and CNRS), and Franco Vazza (U Bologna). Additional postdoc and PhD positions will be advertised in the following years. Frequent visits between the nodes of COSMOMAG are expected for discussions and joint coordination.

The COSMOMAG project aims to pin down the origin of cosmological magnetic fields by developing a unified framework tackling the problem from the initial conditions in the early universe up to present-day observations. The project will study magnetic field generation in the early universe, evolve them numerically, and predict observable signatures today, to be tested via gamma-ray, radio, and gravitational wave observations.

The project consists of understanding the evolution of primordial magnetic fields before recombination. The phenomenology of magnetic field decay is still debated, and numerical simulations are essential to establish correct decay laws. We will mainly use the Pencil Code to simulate magnetic field evolution from generation to recombination, complemented by analytical understanding to interpret results.

Key topics include:

Generation of magnetic fields in the early universe at the end of inflation and during electroweak and QCD phase transitions
Magnetic field evolution through the epoch of recombination

The successful candidate will work with Professor Axel Brandenburg at Nordita, with close collaborations possible with Professors Chiara Caprini, Andrii Neronov, and Franco Vazza. Regular virtual and in-person meetings with other synergy project members and the astrophysics group at Nordita are expected.

Main Responsibilities

Conduct research aligned with the project description under the guidance of the PI.

Qualification Requirements

Hold a Swedish doctoral degree or an equivalent relevant degree from another country.
The degree must be completed no later than the employment decision.

Assessment Criteria:

Advantageous if the doctoral degree was completed no more than three years before the application deadline. Older degrees may also be considered under special circumstances (e.g., sick leave, parental leave, trade union service, clinical attachment, or relevant assignments).
Strong research background and familiarity with numerical simulations are highly valued.

About the Employment

Full-time position for 2–3 years with potential for extension under special circumstances.
Start date by agreement: Spring or Fall 2026.

Benefits

Dynamic interaction between higher education and research in an international environment.
Located in Stockholm’s National City Park with good transport links.
Stockholm University is committed to equal opportunity and a discrimination-free workplace.