PhD position: Helium+ as quantum probe for fundamental constants and new physics

This PhD project is about precisely measuring the internal energy structure (1S-2S transition) of a single He+ ion using quantum technology and advanced lasers to enable new fundamental tests in a search for new physics.

Join the Quantum Metrology and Laser Applications Group at LaserLaB Amsterdam

We are searching for a motivated and interested PhD-student, with a degree in physics or a related topic, who wishes to work with us in the international and stimulating environment of the joint Quantum Metrology and Laser Applications group at LaserLaB Amsterdam. Experience in quantum technology, spectroscopy, or laser physics is appreciated but not a requirement.

The project aims to perform the first precision frequency measurement of the fundamental 1S-2S transition in a single trapped He+ ion. This transition, which can be calculated very accurately, would give exciting prospects to search for new physics. We could perform the best test of higher-order contributions to QED theory (the best tested theory in the Standard Model) to find clues why there are consistent deviations from experiments in neutral helium. Moreover, we could perform the most accurate absolute measurement of the alpha-particle charge radius (complementing the best relative measurement between the alpha and helion particle we recently published in Science 388, page 850). And finally, we could do a nearly hydrogen-independent check of the value of the fundamental Rydberg constant. Experimentally, the idea is to trap a He+ ion together with a Be+ ion in a Paul-trap, and prepare the ions with sympathetic laser cooling via Be+ to the quantum-mechanical ground state. Then we will excite the cold He+ with two ultrashort pulses at 790 nm from an amplified frequency comb laser, combined with 32 nm obtained by high-harmonic generation of those pulses. The measurement method we use has been invented in our lab and is based on quantum interference between the two excitation pulses that are scanned in time on an attosecond time scale (this is made possible by our state-of-the-art infrastructure, which includes atomic clocks and an ultra-stable laser).

During the PhD, you will engage with various aspects of experimental physics, including a broad variety of laser physics such as frequency combs and ultrafast lasers, various forms of nonlinear optics including high-harmonic generation, ultrahigh vacuum, CAD design, ion-trapping and quantum-state control, laser cooling, quantum-logic spectroscopy, electronics, and programming for experimental control and simulations.

Your profile

• Master in physics or related topics
• Affinity for atomic, molecular, and optical physics
• Preferably some experience with experimental techniques
• Most important is that you are bright, enthusiastic, work well in a team, are eager to learn, and of course that you are enthusiastic about this intriguing project!

What do we offer?

A challenging position in a socially engaged organisation. At VU Amsterdam, you contribute to education, research and service for a better world. And that is valuable. So in return for your efforts, we offer you:

• A salary of € 3.059,00 (PhD) and maximum € 3.881,00 (PhD) gross per month in the fourth year, for a full-time employment
• An employment contract of initially 1 year. If there is sufficient perspective, this will be extended to a total of 4 years. Your dissertation at the end of the fourth year forms the end of your employment contract.

We also offer you attractive fringe benefits and arrangements. Some examples:

• A full-time 38-hour working week comes with a holiday leave entitlement of 232 hours per year. If you choose to work 40 hours, you have 96 extra holiday leave hours on an annual basis. For part-timers, this is calculated pro rata.
• 8% holiday allowance and 8.3% end-of-year bonus
• Contribution to commuting expenses
• Optional model for designing a personalized benefits package
• Discount on (and occasionally exclusive access to) theater performances and courses at the Griffioen Cultural Center

About us

QMLA group in the Department of Physics and Astronomy
The Quantum Metrology and Laser Applications group at LaserLaB, Vrije Universiteit Amsterdam, is a very international group, consisting of some 20 strongly collaborating senior and junior scientists. The group focuses on precision measurements of atomic and molecular systems, using advanced laser techniques as well as techniques to cool the motion of atoms and molecules. For this, they use the joint infrastructure at LaserLaB, with a variety of lasers ranging from ultrastable to ultrafast, connected to atomic clocks and frequency comb lasers. The goals are to test fundamental theories of physics (like Quantum Electrodynamics), to determine fundamental constants (like the proton-electron mass ratio), and to search for physics beyond the Standard Model, such as fifth forces and extra dimensions.

Faculty of Science
Researchers and students at VU Amsterdam’s Faculty of Science tackle fundamental and complex scientific problems to help pave the way for a sustainable and healthy future. From forest fires to big data, from obesity to malnutrition, and from molecules to the moon: we cover the full spectrum of the natural sciences. Our teaching and research have a strong experimentally technical, computational and interdisciplinary nature.

We work on new solutions guided by value-driven, interdisciplinary methodologies. We are committed to research, valorisation and training socially engaged citizens of the world who will make valuable contributions to a sustainable, healthy future.

Are you interested in joining the Faculty of Science? You will join undergraduate students, PhD candidates and researchers at the biggest sciences faculty in the Netherlands. You will combine a professional focus with a broad view of the world. We are proud of our collegial working climate, characterised by committed staff, a pragmatic attitude and engagement in the larger whole. The faculty is home to over 11,000 students enrolled in 40 study programmes. It employs over 1,600 professionals spread across 10 academic departments.

Vrije Universiteit Amsterdam
Vrije Universiteit Amsterdam stands for values-driven education and research. We are open-minded experts with the ability to think freely - a broader mind. Maintaining an entrepreneurial perspective and concentrating on diversity, significance and humanity, we work on sustainable solutions with social impact. By joining forces, across the boundaries of disciplines, we work towards a better world for people and planet. Together we create a safe and respectful working and study climate, and an inspiring environment for education and research.

We are located on one physical campus, in the heart of Amsterdam's Zuidas business district, with excellent location and accessibility. Over 6,150 staff work at the VU and over 31,000 students attend academic education.