article published yes Richard Schmidt author Mikhail Lemeshko author 37CB05FA-F248-11E8-B48F-1D18A9856A870000-0002-6990-7802 MiLe department We develop a microscopic theory describing a quantum impurity whose rotational degree of freedom is coupled to a many-particle bath. We approach the problem by introducing the concept of an “angulon”—a quantum rotor dressed by a quantum field—and reveal its quasiparticle properties using a combination of variational and diagrammatic techniques. Our theory predicts renormalization of the impurity rotational structure, such as that observed in experiments with molecules in superfluid helium droplets, in terms of a rotational Lamb shift induced by the many-particle environment. Furthermore, we discover a rich many-body-induced fine structure, emerging in rotational spectra due to a redistribution of angular momentum within the quantum many-body system. American Physical Society2015 eng 1502.03447 00035496990000310.1103/PhysRevLett.114.203001 11420 R. Schmidt, M. Lemeshko, Physical Review Letters 114 (2015). Schmidt R, Lemeshko M. 2015. Rotation of quantum impurities in the presence of a many-body environment. Physical Review Letters. 114(20), 203001. Schmidt, Richard, and Mikhail Lemeshko. “Rotation of Quantum Impurities in the Presence of a Many-Body Environment.” <i>Physical Review Letters</i>, vol. 114, no. 20, 203001, American Physical Society, 2015, doi:<a href="https://doi.org/10.1103/PhysRevLett.114.203001">10.1103/PhysRevLett.114.203001</a>. Schmidt, Richard, and Mikhail Lemeshko. “Rotation of Quantum Impurities in the Presence of a Many-Body Environment.” <i>Physical Review Letters</i>. American Physical Society, 2015. <a href="https://doi.org/10.1103/PhysRevLett.114.203001">https://doi.org/10.1103/PhysRevLett.114.203001</a>. Schmidt R, Lemeshko M. Rotation of quantum impurities in the presence of a many-body environment. <i>Physical Review Letters</i>. 2015;114(20). doi:<a href="https://doi.org/10.1103/PhysRevLett.114.203001">10.1103/PhysRevLett.114.203001</a> R. Schmidt and M. Lemeshko, “Rotation of quantum impurities in the presence of a many-body environment,” <i>Physical Review Letters</i>, vol. 114, no. 20. American Physical Society, 2015. Schmidt, R., &#38; Lemeshko, M. (2015). Rotation of quantum impurities in the presence of a many-body environment. <i>Physical Review Letters</i>. American Physical Society. <a href="https://doi.org/10.1103/PhysRevLett.114.203001">https://doi.org/10.1103/PhysRevLett.114.203001</a> 18132018-12-11T11:54:09Z2025-09-23T10:40:28Z