title: Spin-orbit-coupled fermions in an optical lattice clock.
abstract: Engineered spin-orbit coupling (SOC) in cold-atom systems can enable the study of new synthetic materials and complex condensed matter phenomena. However, spontaneous emission in alkali-atom spin-orbit-coupled systems is hindered by heating, limiting the observation of many-body effects and motivating research into potential alternatives. Here we demonstrate that spin-orbit-coupled fermions can be engineered to occur naturally in a one-dimensional optical lattice clock. In contrast to previous SOC experiments, here the SOC is both generated and probed using a direct ultra-narrow optical clock transition between two electronic orbital states in87Sr atoms. We use clock spectroscopy to prepare lattice band populations, internal electronic states and quasi-momenta, and to produce spin-orbit-coupled dynamics. The exceptionally long lifetime of the excited clock state (160 seconds) eliminates decoherence and atom loss from spontaneous emission at all relevant experimental timescales, allowing subsequent momentum- and spin-resolved in situ probing of the SOC band structure and eigenstates. We use these capabilities to study Bloch oscillations, spin-momentum locking and Van Hove singularities in the transition density of states. Our results lay the groundwork for using fermionic optical lattice clocks to probe new phases of matter.
authors.affiliation: JILA, NIST and University of Colorado, Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: S
authors.initials: S
authors.lastname: Kolkowitz
authors.affiliation: JILA, NIST and University of Colorado, Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: S L
authors.initials: SL
authors.lastname: Bromley
authors.affiliation: JILA, NIST and University of Colorado, Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: T
authors.initials: T
authors.lastname: Bothwell
authors.affiliation: JILA, NIST and University of Colorado, Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: M L
authors.initials: ML
authors.lastname: Wall
authors.affiliation: JILA, NIST and University of Colorado, Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: G E
authors.initials: GE
authors.lastname: Marti
authors.affiliation: JILA, NIST and University of Colorado, Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: A P
authors.initials: AP
authors.lastname: Koller
authors.affiliation: JILA, NIST and University of Colorado, Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: X
authors.initials: X
authors.lastname: Zhang
authors.affiliation: JILA, NIST and University of Colorado, Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Rey
authors.affiliation: JILA, NIST and University of Colorado, Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: J
authors.initials: J
authors.lastname: Ye