@article{12831,
  abstract     = {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.},
  author       = {Zeng, Zhongda and Yakaboylu, Enderalp and Lemeshko, Mikhail and Shi, Tao and Schmidt, Richard},
  issn         = {1089-7690},
  journal      = {The Journal of Chemical Physics},
  number       = {13},
  publisher    = {American Institute of Physics},
  title        = {{Variational theory of angulons and their rotational spectroscopy}},
  doi          = {10.1063/5.0135893},
  volume       = {158},
  year         = {2023},
}