Title | Observation of bound state self-interaction in a nano-eV atom collider |

Publication Type | Journal Article |

Year of Publication | 2018 |

Authors | Thomas, R, Chilcott, M, Tiesinga, E, Deb, AB, Kjærgaard, N |

Journal | Nature Communications |

Volume | 9 |

Issue | 4895 |

Date Published | 2018/11/20 |

Abstract | Quantum mechanical scattering resonances for colliding particles occur when a continuum scattering state couples to a discrete bound state between them. The coupling also causes the bound state to interact with itself via the continuum and leads to a shift in the bound state energy, but, lacking knowledge of the bare bound state energy, measuring this self-energy via the resonance position has remained elusive. Here, we report on the direct observation of self-interaction by using a nano-eV atom collider to track the position of a magnetically-tunable Feshbach resonance through a parameter space spanned by energy and magnetic field. Our system of potassium and rubidium atoms displays a strongly non-monotonic resonance trajectory with an exceptionally large self-interaction energy arising from an interplay between the Feshbach bound state and a different, virtual bound state at a fixed energy near threshold. |

URL | https://arxiv.org/abs/1807.01174 |

DOI | 10.1038/s41467-018-07375-8 |