BEC of polar molecules
Bose-Einstein Condensate of polar molecules! Obtained by evaporating NaCs molecules with two-color microwave shielding. Sebastian Will's lab (Columbia). Nature 631, 289-293 (2024)
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Tijs Karman
Assistant Professor · Radboud University
I am a researcher working in theoretical Atomic, Molecular, and Optical (AMO) Physics. My work focuses on understanding interactions and collisions between ultracold molecules.
Microwave shielding has enabled quantum-degenerate gases of molecules, degenerate Fermi gases and the first molecular Bose-Einstein condensates. Microwave shielding now provides access to dense, strongly interacting molecular gases, opening new opportunities for quantum simulation and many-body physics. We develop molecules as versatile quantum systems for emerging quantum technologies.
Highlights
Microwave shielding
Microwave shield can eliminate two- and three-body loss, and simultaneously enable comprehensive control of interactions between ultracold molecules.
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Sticky collisions
Loss of ultracold molecules is thought to be mediated by "sticky collisions". We work to improve the microscopic understanding of sticky collisions.
Read moreGroup members
Kevin Pérez Álvarez
PhD candidate
Quantum simulation with ultracold molecules.
Nikhila Chandran
PhD candidate
Collision-induced absorption spectroscopy and machine learning
Kang Feng
PhD candidate
Ultracold collisions.
Dr. Hubert Jóźwiak
Marie Curie Postdoctoral Fellow
Shielding and sticking of ultracold molecules
Dr. Hanwei Yang
Postdoctoral Researcher
Ultracold molecules
Former group members
Etienne Walraven
PhD 2021-2026
→ Now postdoc at Purdue University with Valentin Walther
Nathan Jansen
Visiting PhD student 2025
From Michigan State University with Katharine Hunt
Dr. Aleksandra Kiuberis
Postdoc 2024
→ Next at University of Groningen
→ Now in Industry
Publications
A selection of recent publications is listed below. A complete list is available on Google Scholar.
Low-entropy arrays of microwave-shielded molecules prepared by interaction blockade
Tijs Karman, Sebastian Will, and Zoe Z. Yan
Microwave shielding naturally gives rise to an interaction blockade that enables high-fidelity loading of low-entropy arrays for quantum science.
Physical Review Letters (2026)
Extreme loss suppression in an ultracold molecular gas with widely tunable dipolar interactions
Weijun Yuan, Siwei Zhang, Niccolò Bigagli, Haneul Kwak, Claire Warner, Tijs Karman, Ian Stevenson, and Sebastian Will
Demonstrates extreme suppression of two-body and three-body loss of ultracold molecules by microwave shielding, while tuning interactions into the strongly interacting regime.
Science (2026)
Observation of self-bound droplets of ultracold dipolar molecules
Siwei Zhang, Weijun Yuan, Niccolò Bigagli, Haneul Kwak, Tijs Karman, Ian Stevenson, Sebastian Will
Observation of self-bound dipolar droplets of polar molecules.
Nature (2026)Teaching
I am coordinator of the Atomic, Molecular, and Optical (AMO) Physics track in the BSc Physics at Radboud University.
Course information is available in Osiris, course material on Bright Space.
Current teaching- Ultracold Atoms and Molecules (NWI-NM134) 2023/24 - present
- Molecular Physics (NWI-NM089B) 2025/26 - present
- Mechanics, Electricity, and Magnetism 2 (NWI-MOL160) 2024/25 - present
- Computational & Theoretical Chemistry 1 (NWI-MOL174) 2022/23 - 2025/26
- Chemical Bonding (NWI-MOL056) 2021/22 - 2022/23
I supervise BSc and MSc Thesis projects in Physics, Chemistry, and Natural Science. Send me an email to inquire about possible projects.
Short CV
I received my PhD cum laude from Radboud University in 2018 with Gerrit Groenenboom. From 2017, I was a postdoctoral researcher with Jeremy Hutson at Durham University in the UK. Subsequently, I joined the Institute for Theoretical Atomic, Molecular, and Optical Physics (ITAMP) at Harvard University as an independent ITAMP Postdoctoral Fellow, supported by both an NWO Rubicon Fellowship and an ITAMP Fellowship. Since 2021, I have been an Assistant Professor at Radboud University. My research has been recognized by the Elsevier James Brault Early Career Award and the Royal Netherlands Academy of Arts and Sciences (KNAW) Early Career Award.
Contact
Dr. Tijs Karman
Institute for Molecules and Materials
Radboud University
Heyendaalseweg 135
6525 AJ Nijmegen
The Netherlands