Professor Anton Zasedatelev awarded Väisälä grant to study how large particles behave near quantum limit

The Finnish Academy of Science and Letters awarded a three-year Väisälä project grant to four researchers in Finland, including Assistant Professor Anton Zasedatelev of Aalto University's Department of Applied Physics. The grant, worth 200 000 euros, is targeted at early-career researchers.

The Väisälä project grant helps support one of Zasedatelev's main avenues of research at Aalto: how to preserve quantum behaviour in large systems where noise and heat from the environment usually destroy it.

'The Väisälä project grant comes at an important moment, as I started the Macroscopic Quantum Optics group at Aalto in early 2025. This support will allow us to move from theoretical ideas towards experimental implementation in the laboratory and to build the foundations for a new research direction in Finland,' Zasedatelev says.

New particles and unconventional traps

Zasedatelev and the MQO group plan to trap and levitate particles.

'By levitating particles in an ultra-high vacuum, we can study how large objects behave when pushed towards the quantum regime where fundamental noise and quantum effects become important.'

But Zasedatelev has a unique spin on the tried-and-true method. 

'We are trapping a new type of particle made of high-density semiconductor materials and only a few hundred nanometres in size. We use unconventional optical traps, where the particle levitates stably in the dark field of a structured laser trap combined with a radio frequency trap. Our recent study shows that this will strongly suppress decoherence of the particle motion.'

Zasedatelev says the new particles and unconventional optical traps allow for the study of much larger systems than previously. 

'In this case the mass of particles prepared in quantum state can be as high as a trillion atomic mass units. Compared to cold atoms, it puts our platform ahead, by several orders of magnitude, of the largest alkali Bose–Einstein condensates in the mass of an object that can be prepared in a quantum state of its motion.'

Future sensors for weak forces

An improved understanding of how the macroscopic system behaves near the quantum realm could lead to new kinds of ultra-precise sensing equipment for things like gravity, acceleration and electric or magnetic fields.

'The long-term goal is to extend quantum control to increasingly massive systems and use them as exceptionally sensitive probes of weak forces. With the help of the Väisälä grant we will take the next step: building an experiment with an extended coherence time of the large-mass motion in order to explore macroscopic quantum physics in an uncharted regime of large masses.'

In addition to Zasedatelev, the recipients for this round of Väisälä project grants included Antti Moilanen, assistant professor at the University of Eastern Finland, Mirka Saarela, assistant professor at the University of Jyväskylä and Saija Saarni, assistant professor at the University of Turku.

The next call for applications for Väisälä project grants will open in January 2027.