Lemeshko Group

Enderalp has been awarded the Outstanding Scientific Achievement Award at IST Austria for the important results he published in 2017, including:

• E. Yakaboylu, A. Deuchert, M. Lemeshko
  Emergence of non-abelian magnetic monopoles in a quantum impurity problem
  Phys. Rev. Lett. 119, 235301 (2017)

• E. Yakaboylu, M. Lemeshko
  Anomalous screening of quantum impurities by a neutral environment
  Phys. Rev. Lett. 118, 085302 (2017)

• N. Camus*, E. Yakaboylu*, L. Fechner, M. Klaiber, M. Laux, Y. Mi, K. Z. Hatsagortsyan, Th. Pfeifer, Ch. H. Keitel, and R. Moshammer (* = equal contribution)
  Experimental Evidence for Quantum Tunneling Time
  Phys. Rev. Lett. 119, 023201 (2017)

Congratulations, Enderalp!

Enderalp Yakaboylu (Lemeshko group) and Andreas Deuchert (Seiringer group) demonstrated that a molecule rotating inside a superfluid behaves as a non-Abelian magnetic monopole.

E. Yakaboylu, A. Deuchert, M. Lemeshko
Emergence of non-abelian magnetic monopoles in a quantum impurity problem,
Phys. Rev. Lett. 119, 235301 (2017), arXiv:1705.05162

Press coverage: Gismodo, Phys.org, ScienceDaily, EurekAlert, Science Newsline, Sott.net, Resonance.is, Space Daily (in English); der Standard, Pro-Physik, Austria Presse Agentur, Informationsdienst Wissenschaft, Innovations Report, OE Journal, Jura Forum (in German); Webtechno (in Turkish), Egno (in Greek), Dailytechinfo.org (in Russian)

On August 22, Mikhail Lemeshko has been awarded the Ludwig Boltzmann Prize of the Austrian Physical Society for his pioneering work on the angulon quasiparticles. Established in 1953, the prize is awarded once every two years to honor outstanding results achieved by a young researcher in theoretical physics. For more information see the IST press release.

Mikhail Lemeshko receives Boltzmann Prize from APS President Reinhold Koch (credits: Karl Riedling)

Igor has demonstrated that the recently predicted ‘angulon instabilities’ have, in fact, been observed in recent experiments:

• I. N. Cherepanov, M. Lemeshko
  Fingerprints of angulon instabilities in the spectra of matrix-isolated molecules,
  Phys. Rev. Materials 1, 035602 (2017), arXiv:1705.09220

Giacomo has developed a diagrammatic technique to approach angular momentum in quantum many-particle systems. His theory combines the Feynman diagrams of condensed-matter physics with the angular momentum diagrams of atomic and nuclear structure theory:

• G. Bighin, M. Lemeshko
  Diagrammatic approach to orbital quantum impurities interacting with a many-particle environment,
  Phys. Rev. B 96, 085410 (2017), arXiv:1704.02616
  Was selected as an Editor’s suggestion

This summer we are organizing a workshop “Controllable Quantum Impurities in Physics and Chemistry” (CoQIPC 2017), together with the Institute of Theoretical Atomic, Molecular, and Optical Physics (ITAMP, Harvard University).

The workshop will take place August 16–18 at IST Austria (near Vienna).

We aim to bring together people working on quantum impurities in ultracold gases, solid state systems, helium nanodroplets, and beyond.

Hurry up, the registration is open until July 1: http://ist.ac.at/coqipc2017

If you have any questions, just drop a message to Misha Lemeshko

B. Shepperson,  A. S. Chatterley, A. A. Søndergaard, L. Christiansen, M. Lemeshko, H. Stapelfeldt
Strongly aligned molecules inside helium droplets in the near-adiabatic regime,
J. Chem. Phys. 147, 013946 (2017); arXiv:1704.03684

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.

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:

Phys.org, ScienceDaily, EurekAlert, Space Daily (in English),
der Standard, Austria Presse Agentur (in German)
Europapress.es (in Spanish)
Hightech.fm, Echo Moskvy (in Russian)
Kuark.org (in Turkish)
Matfyz.cz (in Czech)
Physics Bimonthly Taiwan (in Chinese)

X. Li, R. Seiringer, M. Lemeshko
Angular self-localization of impurities rotating in a bosonic bath,
Phys. Rev. A 95, 033608 (2017)

We have shown that angulons do form out of molecules rotating in superfluid helium

M. Lemeshko
Quasiparticle approach to molecules interacting with quantum solvents,
Phys. Rev. Lett. 118, 095301 (2017)

Was highlighted as a Physics Viewpoint: A new angle on quantum impurities by Yulia Shchadilova