Coherent rotation of angulons observed in experiment

The angulon theory was able to describe non-adiabatic dynamics of iodine molecules in superfluid helium nanodroplets, as observed in experiments of Henrik Stapelfeldt:

B. Shepperson, A. A. Søndergaard, L. Christiansen, J. Kaczmarczyk, R. E. Zillich, M. Lemeshko,
H. Stapelfeldt
Laser-induced rotation of iodine molecules in He-nanodroplets: revivals and breaking-free,
Phys. Rev. Lett. 118, 203203 (2017)

Interestingly, the revival of alignment observed experimentally can be explained as a rotational revival of the angulon quasiparticle.

The theory was developed by Dr. Jan Kaczmarczyk, a postdoctoral fellow in our group.

A piece on angulons in Physics World

Meet the ‘angulon’, a new quasiparticle found in superfluid helium

by Edwin Cartlidge

“The quasiparticle concept allows physicists to describe complex, many-body interactions in terms of the behaviour of a single particle-like entity. Usually these particles turn up in condensed-matter systems such as semiconductors, but a new type of quasiparticle known as an angulon has been proposed to describe the rotation of an atomic or molecular impurity within a solvent. First proposed theoretically two years ago, angulons have now been shown to explain the curious behaviour of a range of different molecules rotating within liquid helium. …”


See other press releases on angulons:, ScienceDaily, EurekAlert, Space Daily (in English),
der Standard, Austria Presse Agentur (in German) (in Spanish), Echo Moskvy (in Russian) (in Turkish) (in Czech)
Physics Bimonthly Taiwan (in Chinese)