Rotation of quantum impurities in the presence of a many-body environment Schmidt, Richard Lemeshko, Mikhail ; https://orcid.org/0000-0002-6990-7802 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 Society 2015 info:eu-repo/semantics/article doc-type:article text http://purl.org/coar/resource_type/c_2df8fbb1 https://research-explorer.ista.ac.at/record/1813 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> eng info:eu-repo/semantics/altIdentifier/doi/10.1103/PhysRevLett.114.203001 info:eu-repo/semantics/altIdentifier/wos/000354969900003 info:eu-repo/semantics/altIdentifier/arxiv/1502.03447 info:eu-repo/semantics/openAccess