Probing Interactions Between Ultracold Fermions

ORAL

Abstract

At ultracold temperatures, the Pauli exclusion principle suppresses collisions between identical fermions. This has been a strong motivation for the development of optical atomic clocks using fermionic isotopes. However, using a $^{87}$Sr optical lattice clock we recently measured density-dependent frequency shifts of the clock transition. A systematic study of these collision effects has been completed and we have developed a theoretical model which provides a fundamental description of fermionic interactions including the effect of the measurement process on the dynamic evolution of the two particle correlation function. Importantly, for clock operations we have also identified experimental conditions that allow this density shift to be zeroed out.

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Authors

  • Gretchen Campbell

    University of Colorado, JILA, and NIST, JILA, NIST and University of Colorado

  • Andrew Ludlow

    University of Colorado, JILA, and NIST, JILA, NIST and University of Colorado, NIST Boulder, JILA, NIST and Univ. of Colorado

  • Jan Thomsen

    University of Colorado, JILA, and NIST, JILA, NIST and University of Colorado

  • Martin Boyd

    JILA, National Institute of Standards and Technology and University of Colorado, Boulder, CO 80309-0440, USA, JILA, NIST and University of Colorado, JILA and University of Colorado, Boulder, CO 80309, USA

  • Michael Martin

    JILA, NIST and University of Colorado

  • Sebastian Blatt

    University of Colorado, JILA, and NIST, JILA, NIST and University of Colorado

  • Matthew Swallows

    University of Colorado, JILA, and NIST, JILA, NIST and University of Colorado

  • Travis Nicholson

    JILA, NIST and University of Colorado

  • J. Ye

    JILA, National Institute of Standards and Technology and University of Colorado, Boulder, CO 80309-0440, USA, JILA, NIST and University of Colorado, JILA and University of Colorado, Boulder, CO 80309, USA