title: Electromagnetically induced transparency in an entangled medium.
abstract: We theoretically investigate light propagation and electromagnetically induced transparency in a quasi-one-dimensional gas in which atoms interact strongly via exchange interactions. We focus on the case in which the gas is initially prepared in a many-body state that contains a single excitation and conduct a detailed study of the absorptive and dispersive properties of such a medium. This scenario is achieved in interacting gases of Rydberg atoms with two relevant S states that are coupled through exchange. Of particular interest is the case in which the medium is prepared in an entangled spin-wave state. This, in conjunction with the exchange interaction, gives rise to a nonlocal susceptibility that--in comparison to conventional Rydberg electromagnetically induced transparency--qualitatively alters the absorption and propagation of weak probe light, leading to nonlocal propagation and enhanced absorption.
authors.affiliation: School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD, United Kingdom and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China.
authors.forename: Weibin
authors.initials: W
authors.lastname: Li
authors.affiliation: School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD, United Kingdom.
authors.forename: Daniel
authors.initials: D
authors.lastname: Viscor
authors.affiliation: 5. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Hofferberth
authors.affiliation: School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD, United Kingdom.
authors.forename: Igor
authors.initials: I
authors.lastname: Lesanovsky