article published yes Zhongda Zeng author Enderalp Yakaboylu author 38CB71F6-F248-11E8-B48F-1D18A9856A870000-0001-5973-0874 Mikhail Lemeshko author 37CB05FA-F248-11E8-B48F-1D18A9856A870000-0002-6990-7802 Tao Shi author Richard Schmidt author MiLe department Angulon: physics and applications of a new quasiparticle project 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. https://research-explorer.ista.ac.at/download/12831/12841/2023_JourChemicalPhysics_Zeng.pdf application/pdfno https://creativecommons.org/licenses/by/4.0/ American Institute of Physics2023 eng 1089-7690 2211.08070 37031113 00097003880000110.1063/5.0135893 15813 Z. Zeng, E. Yakaboylu, M. Lemeshko, T. Shi, R. Schmidt, The Journal of Chemical Physics 158 (2023). Zeng, Z., Yakaboylu, E., Lemeshko, M., Shi, T., &#38; Schmidt, R. (2023). Variational theory of angulons and their rotational spectroscopy. <i>The Journal of Chemical Physics</i>. American Institute of Physics. <a href="https://doi.org/10.1063/5.0135893">https://doi.org/10.1063/5.0135893</a> Zeng Z, Yakaboylu E, Lemeshko M, Shi T, Schmidt R. 2023. Variational theory of angulons and their rotational spectroscopy. The Journal of Chemical Physics. 158(13), 134301. Z. Zeng, E. Yakaboylu, M. Lemeshko, T. Shi, and R. Schmidt, “Variational theory of angulons and their rotational spectroscopy,” <i>The Journal of Chemical Physics</i>, vol. 158, no. 13. American Institute of Physics, 2023. Zeng Z, Yakaboylu E, Lemeshko M, Shi T, Schmidt R. Variational theory of angulons and their rotational spectroscopy. <i>The Journal of Chemical Physics</i>. 2023;158(13). doi:<a href="https://doi.org/10.1063/5.0135893">10.1063/5.0135893</a> Zeng, Zhongda, et al. “Variational Theory of Angulons and Their Rotational Spectroscopy.” <i>The Journal of Chemical Physics</i>, vol. 158, no. 13, 134301, American Institute of Physics, 2023, doi:<a href="https://doi.org/10.1063/5.0135893">10.1063/5.0135893</a>. Zeng, Zhongda, Enderalp Yakaboylu, Mikhail Lemeshko, Tao Shi, and Richard Schmidt. “Variational Theory of Angulons and Their Rotational Spectroscopy.” <i>The Journal of Chemical Physics</i>. American Institute of Physics, 2023. <a href="https://doi.org/10.1063/5.0135893">https://doi.org/10.1063/5.0135893</a>. 128312023-04-16T22:01:07Z2025-04-23T08:55:25Z