title: Strongly Interacting Gas of Two-Electron Fermions at an Orbital Feshbach Resonance.
abstract: We report on the experimental observation of a strongly interacting gas of ultracold two-electron fermions with an orbital degree of freedom and magnetically tunable interactions. This realization has been enabled by the demonstration of a novel kind of Feshbach resonance occurring in the scattering of two (173)Yb atoms in different nuclear and electronic states. The strongly interacting regime at resonance is evidenced by the observation of anisotropic hydrodynamic expansion of the two-orbital Fermi gas. These results pave the way towards the realization of new quantum states of matter with strongly correlated fermions with an orbital degree of freedom.
authors.affiliation: Department of Physics and Astronomy, University of Florence, I-50019 Sesto Fiorentino, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Pagano
authors.affiliation: Department of Physics and Astronomy, University of Florence, I-50019 Sesto Fiorentino, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Mancini
authors.affiliation: LENS European Laboratory for Nonlinear Spectroscopy, I-50019 Sesto Fiorentino, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Cappellini
authors.affiliation: LENS European Laboratory for Nonlinear Spectroscopy, I-50019 Sesto Fiorentino, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Livi
authors.affiliation: LENS European Laboratory for Nonlinear Spectroscopy, I-50019 Sesto Fiorentino, Italy.|INRIM Istituto Nazionale di Ricerca Metrologica, I-10135 Torino, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Sias
authors.affiliation: LENS European Laboratory for Nonlinear Spectroscopy, I-50019 Sesto Fiorentino, Italy.|INO-CNR Istituto Nazionale di Ottica del CNR, Sezione di Sesto Fiorentino, I-50019 Sesto Fiorentino, Italy.|INFN Istituto Nazionale di Fisica Nucleare, Sezione di Firenze, I-50019 Sesto Fiorentino, Italy.
authors.forename: J
authors.initials: J
authors.lastname: Catani
authors.affiliation: Department of Physics and Astronomy, University of Florence, I-50019 Sesto Fiorentino, Italy.|LENS European Laboratory for Nonlinear Spectroscopy, I-50019 Sesto Fiorentino, Italy.|INRIM Istituto Nazionale di Ricerca Metrologica, I-10135 Torino, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Inguscio
authors.affiliation: Department of Physics and Astronomy, University of Florence, I-50019 Sesto Fiorentino, Italy.|LENS European Laboratory for Nonlinear Spectroscopy, I-50019 Sesto Fiorentino, Italy.|INFN Istituto Nazionale di Fisica Nucleare, Sezione di Firenze, I-50019 Sesto Fiorentino, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Fallani