Browsing by Author "Demler, E."

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    Creation of Rydberg Polarons in a Bose Gas
    (American Physical Society, 2018) Camargo, F.; Schmidt, R.; Whalen, J.D.; Ding, R.; Woehl, G. Jr.; Yoshida, S.; Burgdörfer, J.; Dunning, F.B.; Sadeghpour, H.R.; Demler, E.; Killian, T.C.
    We report spectroscopic observation of Rydberg polarons in an atomic Bose gas. Polarons are created by excitation of Rydberg atoms as impurities in a strontium Bose-Einstein condensate. They are distinguished from previously studied polarons by macroscopic occupation of bound molecular states that arise from scattering of the weakly bound Rydberg electron from ground-state atoms. The absence of a p-wave resonance in the low-energy electron-atom scattering in Sr introduces a universal behavior in the Rydberg spectral line shape and in scaling of the spectral width (narrowing) with the Rydberg principal quantum number, n. Spectral features are described with a functional determinant approach (FDA) that solves an extended Fröhlich Hamiltonian for a mobile impurity in a Bose gas. Excited states of polyatomic Rydberg molecules (trimers, tetrameters, and pentamers) are experimentally resolved and accurately reproduced with a FDA.
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    Theory of excitation of Rydberg polarons in an atomic quantum gas
    (American Physical Society, 2018) Schmidt, R.; Whalen, J.D.; Ding, R.; Camargo, F.; Woehl, G. Jr.; Yoshida, S.; Burgdörfer, J.; Dunning, F.B.; Demler, E.; Sadeghpour, H.R.; Killian, T.C.
    We present a quantum many-body description of the excitation spectrum of Rydberg polarons in a Bose gas. The many-body Hamiltonian is solved with a functional determinant approach, and we extend this technique to describe Rydberg polarons of finite mass. Mean-field and classical descriptions of the spectrum are derived as approximations of the many-body theory. The various approaches are applied to experimental observations of polarons created by excitation of Rydberg atoms in a strontium Bose-Einstein condensate.