Prof. Dr. Ana Achúcarro

Professor Astroparticle physics and quantum field theory / Head of MSc Physics


Leiden University


Physicists at the Leiden Institute of Physics (LION) conduct fundamental research into physical phenomena. They are inspired by curiosity and the desire to know more about the world in which we live. This research has always paved the way for new practical applications. These are something that the researchers at LION are always on the lookout for.

This approach goes back to the beginning of the 20th century, when Hendrik Antoon Lorentz and Heike Kamerlingh Onnes won Nobel Prizes in Physics. These turned out to be the prelude to a period in which celebrated scientists such as Paul Ehrenfest, Lorentz, Onnes and guest professor Albert Einstein contributed to several revolutions in physics and astronomy, such as relativity theory, quantum mechanics, liquefaction of helium and the discovery of superconductivity.

Leiden Institute of Physics (LION)

Theoretical and Experimental

Even at that time, there were already close links at Leiden between the theoretical physicists, who aim to understand and predict phenomena, and the experimental physicists, whose experiments in the laboratory are designed to push the boundaries of what is practicable and measurable.

There are therefore two prongs to the research at LION: theoretical physics is accommodated in the Lorentz Institute and experimental physics in the Huygens-Kamerlingh Onnes Laboratory.

Quantum world, universe & life and instrument development

Quantum World
An important area of research at Leiden is the quantum world, the counterintuitive physics of the infinitesimal. Experimentalists in the Quantum Matter and Optics Theme are working on the development of building blocks for quantum information networks, where the information carrier is light (photons). Theoreticians are developing quantum algorithms that will enable future quantum computers to perform complex calculations much faster. This will open up a whole new world for developing new types of molecules and materials.

Theoretical and experimental physicists are also researching phenomena that spin off from this quantum mechanics, such as superconductivity at very low temperatures, as discovered by Kamerlingh Onnes back in 1911. Superconductivity is used in MRI scanners and energy-efficient power cables.

The universe and life
Cosmology is a discipline where physicists and astronomers meet. Leiden theoreticians are working closely with the astronomers from the Leiden Observatory to investigate the links between particle physics, the Big Bang, the expansion of the universe, and dark energy and matter.

A third research area is the physics of Biological, Soft and Complex Systems, ranging from individual molecules, such as DNA, to entire cells. Questions about how cells perform their tasks, exchange signals, move or exert forces often lie within the domain of physics, and they can even lead to applications in the biomedical field. Leiden physicists are also researching soft materials, such as colloids for building microrobots, the physics of networks and the folding of materials.

Instrument development
Alongside the link between theory and experiments, another long-standing Leiden tradition is the development of instruments. An example of ongoing work at LION is creating different types of extremely sensitive microscopes for researching materials and phenomena. This exceptional equipment is being developed in close collaboration with the Faculty of Science’s Fine Mechanics and Electronics expertise centre, which in turn can call upon the talents of its ‘neighbours’: the Leiden Instrument Makers School (LiS), founded in 1901 by Kamerlingh Onnes.


PhD Programme and Research schools

PhD Programme
LION offers a PhD program in which candidates carry out independent research on a specific topic, culminating in a PhD thesis.

If you are a prospective PhD student, click here. All of our PhD projects are 4-year fully paid positions, usually consisting of a 1-year+3-year contract. Apart from working on their research project, the PhD student contributes to the teaching at the institute (as a teaching assistant, and as a supervisor a few BSc or MSc students). You will also be asked to take part in courses and workshops suitable for your scientific and personal development.

Research Schools
Once you have started your PhD project at LION, you will automatically become part of the Faculty of Science Graduate School (click here for more information). Together with Leiden University, the Graduate School offers transferable skills courses. At the same time, you will also become part of the Casimir Research School and, if you are a PhD student at the Lorentz Institute, of the Dutch Research School of Theoretical Physics.

The research schools offer a diverse program of research related courses, seminars, workshops and conferences. All of this – the research plan and the teaching and education requirements – will be documented in a personal education and supervision plan, that is drawn up by the supervisor and the PhD student within three months after the contract starts.

Wellbeing and Counseling

At LION, we value the wellbeing of our PhD students – like every other employee PhD students have the right to work in a safe and stimulating environment. In order to be able to adapt to the PhD student’s needs, LION has several formal and informal structures in place. For example, apart from your promotor and daily supervisor, we assign a second supervisor to each PhD student.

Both of them have a say at the PhD student’s go/no-go meeting in their tenth month of their contract. Furthermore, the Casimir Research School offers each PhD student the opportunity to have an informal meet-up with a more senior PhD student from outside the PhD student’s research group, so any problems or challenges can be discussed in a relaxed atmosphere.

However, problems may arise that you don’t know how to solve by yourself or with the help of your (second) supervisor. In such cases, it’s good to know that you can always can turn to one of our confidential counselors.