title: Quasiparticle Approach to Molecules Interacting with Quantum Solvents.
abstract: Understanding the behavior of molecules interacting with superfluid helium represents a formidable challenge and, in general, requires approaches relying on large-scale numerical simulations. Here, we demonstrate that experimental data collected over the last 20 years provide evidence that molecules immersed in superfluid helium form recently predicted angulon quasiparticles [Phys. Rev. Lett. 114, 203001 (2015)PRLTAO0031-900710.1103/PhysRevLett.114.203001]. Most important, casting the many-body problem in terms of angulons amounts to a drastic simplification and yields effective molecular moments of inertia as straightforward analytic solutions of a simple microscopic Hamiltonian. The outcome of the angulon theory is in good agreement with experiment for a broad range of molecular impurities, from heavy to medium-mass to light species. These results pave the way to understanding molecular rotation in liquid and crystalline phases in terms of the angulon quasiparticle.
authors.affiliation: IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400 Klosterneuburg, Austria and Kavli Institute for Theoretical Physics, University of California, Santa Barbara, California 93106, USA.
authors.forename: Mikhail
authors.initials: M
authors.lastname: Lemeshko