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The angulon quasiparticle: from molecules in superfluids to ultrafast magnetism

Event Details

Event Dates: 

Thursday, April 5, 2018 - 11:00am

Seminar Location: 

  • JILA X317

Speaker Name(s): 

Mikhail Lemeshko

Speaker Affiliation(s): 

Institute of Science and Technology, Austria
Seminar Type/Subject

Scientific Seminar Type: 

  • Other

Seminar Type Other: 

AMO Theory seminar

Event Details & Abstract: 

Recently we have predicted a new quasiparticle - the angulon - which is formed when a quantum impurity (such as an electron, atom, or molecule) exchanges its orbital angular momentum with a many-particle environment (such as lattice phonons or a Fermi sea) [1,2].

Soon thereafter we obtained strong evidence that angulons are formed in experiments on molecules trapped inside superfluid helium nanodroplets [3].

The angulon theory thereby provided a simple explanation for experimental data accumulated during the last two decades. Moreover, casting the many-particle problem in terms of angulons amounts to a drastic simplification and allows to tackle previously intractable problems related to quantum dynamics [4].

In this presentation we will introduce the angulon concept and discuss novel physical phenomena [1,5,6] arising from the angular momentum exchange in quantum many-particle systems. We will describe the applications of angulons to modern experiments on quantum impurities and on non-equilibrium magnetism [7].

[1] R. Schmidt, M. Lemeshko, Phys. Rev. Lett. 114, 203001 (2015) [2] R. Schmidt, M. Lemeshko, Phys. Rev. X 6, 011012 (2016) [3] M. Lemeshko, Phys. Rev. Lett., 118, 095301 (2017); Viewpoint: Physics 10, 20 (2017)

[4] B. Shepperson, A. A. Sondergaard, L. Christiansen, J. Kaczmarczyk, R. E. Zillich, M. Lemeshko, H. Stapelfeldt, Phys. Rev. Lett. 118, 203203 (2017) [5] E. Yakaboylu, M. Lemeshko, Phys. Rev. Lett. 118, 085302 (2017) [6] E. Yakaboylu, A. Deuchert, M. Lemeshko, Phys. Rev. Lett. 119, 235301 (2017)

[7] J.H. Mentink, M.I. Katsnelson, M. Lemeshko, arXiv:1802.01638 (2018)