Rotation of coupled cold molecules in the presence of a many-body environment

Li X. 2020. Rotation of coupled cold molecules in the presence of a many-body environment. Institute of Science and Technology Austria.

Download
OA THESIS_Xiang_Li.pdf 3.62 MB [Published Version]

Thesis | PhD | Published | English
Department
Series Title
ISTA Thesis
Abstract
The oft-quoted dictum by Arthur Schawlow: ``A diatomic molecule has one atom too many'' has been disavowed. Inspired by the possibility to experimentally manipulate and enhance chemical reactivity in helium nanodroplets, we investigate the rotation of coupled cold molecules in the presence of a many-body environment. In this thesis, we introduce new variational approaches to quantum impurities and apply them to the Fröhlich polaron - a quasiparticle formed out of an electron (or other point-like impurity) in a polar medium, and to the angulon - a quasiparticle formed out of a rotating molecule in a bosonic bath. With this theoretical toolbox, we reveal the self-localization transition for the angulon quasiparticle. We show that, unlike for polarons, self-localization of angulons occurs at finite impurity-bath coupling already at the mean-field level. The transition is accompanied by the spherical-symmetry breaking of the angulon ground state and a discontinuity in the first derivative of the ground-state energy. Moreover, the type of symmetry breaking is dictated by the symmetry of the microscopic impurity-bath interaction, which leads to a number of distinct self-localized states. For the system containing multiple impurities, by analogy with the bipolaron, we introduce the biangulon quasiparticle describing two rotating molecules that align with respect to each other due to the effective attractive interaction mediated by the excitations of the bath. We study this system from the strong-coupling regime to the weak molecule-bath interaction regime. We show that the molecules tend to have a strong alignment in the ground state, the biangulon shows shifted angulon instabilities and an additional spectral instability, where resonant angular momentum transfer between the molecules and the bath takes place. Finally, we introduce a diagonalization scheme that allows us to describe the transition from two separated angulons to a biangulon as a function of the distance between the two molecules.
Publishing Year
Date Published
2020-12-21
Page
125
ISSN
IST-REx-ID

Cite this

Li X. Rotation of coupled cold molecules in the presence of a many-body environment. 2020. doi:10.15479/AT:ISTA:8958
Li, X. (2020). Rotation of coupled cold molecules in the presence of a many-body environment. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:8958
Li, Xiang. “Rotation of Coupled Cold Molecules in the Presence of a Many-Body Environment.” Institute of Science and Technology Austria, 2020. https://doi.org/10.15479/AT:ISTA:8958.
X. Li, “Rotation of coupled cold molecules in the presence of a many-body environment,” Institute of Science and Technology Austria, 2020.
Li X. 2020. Rotation of coupled cold molecules in the presence of a many-body environment. Institute of Science and Technology Austria.
Li, Xiang. Rotation of Coupled Cold Molecules in the Presence of a Many-Body Environment. Institute of Science and Technology Austria, 2020, doi:10.15479/AT:ISTA:8958.
All files available under the following license(s):
Copyright Statement:
This Item is protected by copyright and/or related rights. [...]
Main File(s)
File Name
Access Level
OA Open Access
Date Uploaded
2020-12-22
MD5 Checksum
3994c54a1241451d561db1d4f43bad30

Source File
File Name
Access Level
Restricted Closed Access
Date Uploaded
2020-12-22
MD5 Checksum
0954ecfc5554c05615c14de803341f00

Export

Marked Publications

Open Data ISTA Research Explorer

Search this title in

Google Scholar