Variational theory of angulons and their rotational spectroscopy
The angulon, a quasiparticle formed by a quantum rotor dressed by the excitations of a many-body bath, can be used to describe an impurity rotating in a fluid or solid environment. Here, we propose a coherent state ansatz in the co-rotating frame, which provides a comprehensive theoretical descripti...
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| Hauptverfasser: | , , , , |
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| Dokumenttyp: | Article (Journal) |
| Sprache: | Englisch |
| Veröffentlicht: |
3 April 2023
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| In: |
The journal of chemical physics
Year: 2023, Jahrgang: 158, Heft: 13, Pages: 1-13 |
| ISSN: | 1089-7690 |
| DOI: | 10.1063/5.0135893 |
| Online-Zugang: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1063/5.0135893
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| Verfasserangaben: | Zhongda Zeng, Enderalp Yakaboylu, Mikhail Lemeshko, Tao Shi, and Richard Schmidt |
| Zusammenfassung: | The angulon, a quasiparticle formed by a quantum rotor dressed by the excitations of a many-body bath, can be used to describe an impurity rotating in a fluid or solid environment. Here, we propose a coherent state ansatz in the co-rotating frame, which provides a comprehensive theoretical description of angulons. We reveal the quasiparticle properties, such as energies, quasiparticle weights, and spectral functions, and show that our ansatz yields a persistent decrease in the impurity’s rotational constant due to many-body dressing, which is consistent with experimental observations. From our study, a picture of the angulon emerges as an effective spin interacting with a magnetic field that is self-consistently generated by the molecule’s rotation. Moreover, we discuss rotational spectroscopy, which focuses on the response of rotating molecules to a laser perturbation in the linear response regime. Importantly, we take into account initial-state interactions that have been neglected in prior studies and reveal their impact on the excitation spectrum. To examine the angulon instability regime, we use a single-excitation ansatz and obtain results consistent with experiments, in which a broadening of spectral lines is observed while phonon wings remain highly suppressed due to initial-state interactions. |
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| Beschreibung: | Gesehen am 23.06.2023 |
| Beschreibung: | Online Resource |
| ISSN: | 1089-7690 |
| DOI: | 10.1063/5.0135893 |