Steven Hoekstra

I am an experimental physicist specialised in the development and application of precision measurement techniques to explore the limits of particle physics. In my group we perform experiments with small quantum systems (atoms, ions, molecules) and nanoparticles. The main tools we use to study these particles are lasers, and external electric and magnetic fields. The experiments we do are typically in a very well controlled environment, shielded from all unwanted background. By doing this, the subtle effects of quantum physics become visible, and we can use these atoms, ions, molecules and nanoparticles for a range of exciting experiments.

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[July 2025] There is an upcoming vacancy for a research technician in our group. Stay tuned, and contact me if you are interest to talk about possibilities!

Projects

NL-eEDM

Our research program to measure the electron's electric dipole moment using a cold, slow and intense beam of BaF molecules

Levitated nanospheres

We optically levitate and cool nanospheres, to explore their use as sensitive sensors.

Publications

Community input to the European Strategy on particle physics: Searches for Permanent Electric Dipole Moments

M. Athanasakis-Kaklamanakis, M. Au, R. Berger, S. Degenkolb, J. De Vries, S. Hoekstra, A. Keshavarzi, N. Neri, D. Ries, P. Schmidt-Wellenburg, M. Tarbutt

ArXiv, pp. 2505.22281

2D transverse laser cooling of a hexapole focused beam of cold BaF molecules

Joost W.F. van Hofslot, Izabella E. Thompson, Anno Touwen, Nithesh Balasubramanian, Roman Bause, Hendrick L. Bethlem, Anastasia Borschevsky, Ties H. Fikkers, Steven Hoekstra, Steven A. Jones, Jelmer E.J. Levenga, Maarten C. Mooij, Heleen Mulder, Bastiaan A. Nijman, Efion H. Prinsen, Bart J. Schellenberg, Lucas van Sloten, Rob G.E. Timmermans, Wim Ubachs, Jordy de Vries, Lorenz Willmann

ArXiv:2506.19069, June, 2025

A method to determine the phase-space distribution of a pulsed molecular beam

Maarten C Mooij, Hendrick L Bethlem, Alexander Boeschoten, Anastasia Borschevsky, Ties H Fikkers, Steven Hoekstra, Joost W F van Hofslot, Klaus Jungmann, Virginia R Marshall, Thomas B Meijknecht, Rob G E Timmermans, Anno Touwen, Wim Ubachs, Lorenz Willmann, (NL-eEDM collaboration)

J. Phys. B: At. Mol. Opt. Phys., vol. 58, 2025, p. 015303

Prospects for measuring the electron's electric dipole moment with polyatomic molecules in an optical lattice

Roman Bause, Nithesh Balasubramanian, Ties Fikkers, Eifion H. Prinsen, Kees Steinebach, Arian Jadbabaie, Nicholas R. Hutzler, I. Agustín Aucar, Lukáš F. Pašteka, Anastasia Borschevsky, Steven Hoekstra

Physical Review A, vol. 111, 2025, p. 062815

Manipulating a beam of barium fluoride molecules using an electrostatic hexapole

Anno Touwen, Joost W.F. van Hofslot, Thijs Qualm, Richard Borchers, Roman Bause, Hendrick L. Bethlem, Alexander Boeschoten, Anastasia Borschevsky, Ties H. Fikkers, Steven Hoekstra, Klaus Jungmann, Virginia R. Marshall, Thomas B. Meijknecht, Maarten C. Mooij, Rob G.E. Timmermans, Wim Ubachs, Lorenz Willmann

New Journal of Physics, vol. 26, 2024, p. 073054

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Teaching

Activities

Quantum universe master program

I am the coordinator of the Quantum Universe master program, one of the main specialisation at the interface of physics, astronomy, mathematics and cosmology at the University of Groningen.

Courses

Electricity and Magnetism

1st year physics, applied physics and astronomy

I have taught this course from 2017-2023. The number of students has grown gradually, to about 340 students in 2022-2023.

Waves and Optics

2nd year physics, applied physics and astronomy

I have started teaching this course in 2019, and I have transformed it from traditional teaching to problem-based learning. Typically about 190 students take this course.

From small to large to life

For honours college students of FSE.

I have given this course in 2019-2021. for about 25 students, twice a year.

The Quantum World

3rd year broadening minor - university wide.

This is a course on quantum physics for non-physics students, part of the broadening minor 'Einstein's Physics: Space-time and Parallel Worlds'. About ~ 150 students take this course.

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Theses

Bachelor & Master research projects

Media

Our work in the media